Skip to main content

Questions tagged [number-sequence]

A puzzle in which the hidden pattern behind a given sequence of numbers (and, often, the next term) is to be found. Use with [sequence]

Filter by
Sorted by
Tagged with
59 votes
4 answers
10k views

Interview Question or Pathbreaking puzzle

I thought this changes the way series of numbers are looked at 1 1 1 2 1 1 2 1 1 Write down the next three lines
skv's user avatar
  • 5,002
25 votes
1 answer
3k views

Four is Cosmic!

This is a little puzzle I heard a while back from one of my mathematically inclined friends- I get the sense that it's bounced around a little, so forgive me if you've heard it. There is a sort of ...
Patrick N's user avatar
  • 1,790
4 votes
1 answer
441 views

Number sequences: 6X000X9, 700XX08,00000015,?,00000015

Here is the question: 6X000X9,700XX08,00000015,?,00000015,?,00000015 This question actually comes from the puzzles made by my friend. He gave me his puzzles recently but I couldn't figure it out. ...
LETTERKING's user avatar
4 votes
1 answer
2k views

Missing number in this sequence?

I heard this puzzle in a quiz I participated in: 10, 11, 12, 13, 14, 15, 16, 17, 20, 22, 24, ?, 100, 121, 10000 What is the missing number? (You don't need to do any big calculations, and you don't ...
Rand al'Thor's user avatar
13 votes
1 answer
589 views

Two honeycomb hints (yet another 'find the next number in the sequence')

Find the next number in the sequence $1,7,74,\dots$ First hint: Second hint: To clarify: the 'hints' are really clues. They are hidden, because any of the two alone could be enough to solve the ...
Yuriy S's user avatar
  • 997
6 votes
8 answers
50k views

Fill the holes? [closed]

You have to fill the boxes to make the equation true:   +   +   = 30 Using only 1, 3, 5, 7, 9, 11, 13, 15. You can also repeat the numbers. (eg: 1 + 1 + 1) Edit1: the boxes of the equation are empty ...
Thomas Ayoub's user avatar
-2 votes
1 answer
10k views

What is the next number and why? - 11,21,1112,… [duplicate]

Simple logic question, what is the next number and why? 11, 21, 1112, 3112, 211213, 312213, 212223, 114213, ?
Skalwalker's user avatar
65 votes
1 answer
4k views

Mysterious message from the NoSlaves™ Calculator Co

So my son is starting to show an interest in mathematics, and being the awesome dad that I am, I decided to buy him a basic calculator. Being the cheapskate that I am, I ordered the cheapest one I ...
Alconja's user avatar
  • 37.3k
1 vote
2 answers
4k views

What is the next number? 24,54,90,120,168,210,240,288,360,440 [closed]

Question : What is the next number in the following sequence? (not finite) $$\large24,54,90,120,168,210,240,288,360,440,\dots$$ My Solution I'm trying a closed form solution I tried computing the ...
Reptilian's user avatar
-1 votes
3 answers
1k views

Complete the number-sequence

2 → 6 3 → 12 4 → 20 5 → 30 6 → 42 9 → ? Can you find a correspondence between these numbers? It's not mine, so I don't take any credit. I've just seen it in Linkedin and wanted to share with ...
David Sánchez's user avatar
28 votes
2 answers
33k views

What is this magic trick with 6 cards featuring numbers between 1 and 60?

I hope this is on topic. I have a set of kids' magic tricks but I have lost the instructions! I was hoping this might be a good place to get some help. Here is the first one. What is the trick and ...
Simd's user avatar
  • 7,845
23 votes
1 answer
4k views

Very simple, yet unsolved, sequence of numbers

A simple sequence of numbers, which I encountered during intermediate school, in my math book. Any person that finished intermediate school possesses the necessary toolbox required to solve this ...
RickardNi's user avatar
  • 365
23 votes
1 answer
1k views

A Sequence That Keeps Changing?

So I get this special sequence of "items" as the following: 2 1 3 4 7 8 2 5 2 3 9 But look! If I put some numbers (randomly) in front of the sequence: 3 4 2 1 3 4 7 8 2 5 2 3 8 And yeah! ...
athin's user avatar
  • 34.2k
10 votes
3 answers
595 views

Two missing numbers

Two numbers go at the $?$s, what are they and why? $733,\space \space 716,\space \space 645,\space \space 565,\space \space 324,\space \space 276,\space \space 77,\space \space 75,\space \space 64,\...
Jonathan Allan's user avatar
10 votes
2 answers
2k views

Seeing the forest for the trees and all that jazz

No math involved here, just a bit of lateral thinking. Can you figure out what comes next? 2, 4, 8, 4, 4, 1, 3, 2, 7, 8, 3, 3, 6, 3, 4, 5... Bonus: How about here? 6, 3, 6, 3, 3, 5, 3, 3, 4...
Luke's user avatar
  • 1,728
10 votes
6 answers
2k views

A tricky batch of four number sequences

What are the next few numbers in each of these integer sequences? Each of them has a clear and justifiable solution. 1, 2, 3, 5, 8, 9, 12, 20, 21, 22, ??, ??, ... 50, 49, 48, 46, 45, 44, 43, 38, ..., ...
user avatar
10 votes
1 answer
1k views

What is the next integer in this sequence?

First, I offer you a little something to put you in the right spirits: For many many years, black cats have had some interesting associations and reputations, which no doubt helped inspire The Black ...
Rubio's user avatar
  • 41.7k
7 votes
1 answer
551 views

What happened to the Fibonacci sequence?

I'm sure you've seen some of these numbers before: 1 3 8 13 21 30 36 45 54 63 Whats the next number in the sequence? And what have I done to the Fibonacci ...
Reinis Mazeiks's user avatar
-3 votes
4 answers
606 views

What is the missing number and pattern in this sequence?

The puzzle has already been solved but you can still try it just for fun without looking at the posted correct answer. What is the missing number in the following sequence?: 0, 4, 10, 32, ?, 317 .....
David James's user avatar
25 votes
1 answer
867 views

Oh dear, oh my, how blatant

Looking at the Puzzling Stack Exchange recently, I found a surfeit of number sequence riddles that all look the same! I mean, there's no difference between any of them. I'm sick and tired of all these ...
Austin Weaver's user avatar
20 votes
1 answer
767 views

What is the last integer in this sequence?

Here are the first several entries in a finite sequence of integers. $$ 31, 45, 71, 89, 91, 94, 111, 112, 118, 121, 126, 131, $$ $$ 134, 135, 139, 143, 144, 145, 148, 158, 161, 189, 193, 194, \dots $$ ...
Rubio's user avatar
  • 41.7k
18 votes
6 answers
2k views

Important days in history... and to come!

The other day I decided I wanted to come up with another simple puzzle before releasing another toughy on puzzling.SE. I came across an interesting series of dates that I wanted to share and see if ...
Z. Dailey's user avatar
  • 3,580
17 votes
2 answers
1k views

Logically linked numbers

The left and right numbers are linked. What should the last number on the right be, and why? \begin{align} 135759&: 1 \\ 151364&: 4 \\ 255075&: 9 \\ 279422&: 36 \\ 292620&: 91 \\ ...
Jonathan Allan's user avatar
17 votes
2 answers
932 views

16 number puzzles on a blackboard

I have left you some number puzzles on the blackboard. Solve them and let me know what they spell. Hint:
DenverCoder1's user avatar
  • 10.5k
16 votes
5 answers
2k views

Should the angels play their game?

Two angels in heaven want to play a game. One of them comes up with an arbitrary, computable function from the integers to the integers. The other angel has to guess what it is. The second angel can ...
Kevin's user avatar
  • 1,283
15 votes
2 answers
780 views

Can you generate the next number in this integer series and describe the rule?

2, 3, 5, 7, ... 11, 13, 17, ... 25, 29, ... 35, ... 43, 47, 49, ... 53, 59, 61, 65, 67, ... 71, ... ?? The answer (indicated by two question marks) has two digits. When you see '...', it means that ...
chasly - supports Monica's user avatar
15 votes
9 answers
4k views

Number-sequence puzzle where the number goes down in the middle

My friend asked me for help with an IQ test and after she did it online she came back at me with the ones she couldn't solve. Two of them however, I discovered are the same puzzle type, but no ...
Folaht's user avatar
  • 261
13 votes
1 answer
643 views

Find the next number in this sequence

Find the next number in the sequence : 1; 5; 33; 25; 2; 16; 14; 12; 11; ? What is the next number and why ?
Rémi Henry's user avatar
  • 1,581
13 votes
3 answers
2k views

Three different, and somewhat difficult, sequence puzzles

Here are three different letter/number sequences. Try to solve as many as possible. The spoilers give hints to each sequence in the form of how many elements are in the corresponding sequence. ...
GamrCorps's user avatar
  • 686
13 votes
1 answer
2k views

Really, really, really hard sequence

... in which you have nothing to do with math ... except maybe with some counting and this and that ... but no calculations, no, definitely no. $1, 0, 8, 62, 90, 68, 83, 89, 88, 057, 619, 028, 693,...
kamenf's user avatar
  • 6,506
12 votes
2 answers
2k views

What is the next number in this sequence? 0, 1, 11.2, 10.2, 113.2, 103, 103.2, 0.2, 1.2, 2.2, 2, …

0, 1, 11.2, 10.2, 113.2, 103, 103.2, 0.2, 1.2, 2.2, 2, ? The only hint I'll give at this stage is that the sequence is infinite. If nobody gets it within a few days, I'll give a few terms that come ...
h34's user avatar
  • 4,569
12 votes
2 answers
1k views

Introducing S-sequences: which is the shortest to contain all integers 1 to 20?

Consider a sequence (finite or infinite) of different positive integers, such as the following, in which the first term is 1, and thereafter the nth term is either the previous term plus n, minus n, ...
Bernardo Recamán Santos's user avatar
12 votes
3 answers
759 views

Cryptobiology? Biocryptology?

I have a friend who is a self-proclaimed cryptobiologist. Okay, maybe I don't, but if I did, I like to think she would have presented me with this puzzle: Find the hidden message: 441344•...
SendersReagent's user avatar
11 votes
2 answers
988 views

Numbers in the series: The British way

What are the next two numbers in series? Six hundred and forty Five thousand Eight thousand ? ? What are the next two numbers? Is this a trick question? Note: I am using ...
DrD's user avatar
  • 39.2k
10 votes
6 answers
939 views

A Game Of Cat And Mouse: Part 2

Part 1 can be found here. Information from Part 1 is not required to solve this puzzle. Having identified where El Gato intends to strike next, you charter one of the Bureau's jets and fly off to ...
F1Krazy's user avatar
  • 8,058
9 votes
1 answer
397 views

Sequence seen on the street

I was walking on the street when I saw the following numbers: $0, 7, 2, 3, 9$ The sequence continued a bit further then looped back. However, it was not the sequence I was expecting, so it took me ...
OxTaz's user avatar
  • 303
9 votes
1 answer
822 views

A sequence about you (Puzzling Stack Exchange users)

I have a mysterious sequence for you... $204, 186, 172, 133, 126, 123, 120, 119, 111, 107, 102, 96, 90, 87, 86, 86, 85, 79, 75, 73, 70, 68, 66, 66, 65, 65, 65, 64, 64, 64, ...$ This sequence may ...
palsch's user avatar
  • 851
8 votes
2 answers
454 views

A sequence defined by a single fraction

I have a sequence of numbers here, which follow a very simple rule that can be expressed using a single fraction: 1, 2, 10, 11, 13, 15, 20, 22, 25, 28, ... What is this rule (in particular, what ...
user avatar
8 votes
2 answers
786 views

IX-NAY on the IX-SAY

Will this sequence ever have a 6 in it? 9, 1, 1, 1, 10, 3, 1, 1, 10, 5, 1, 1, 10, 1, 5, 2, 1, 1, 10, 1, 1, 1, 5, 4, 1, 1, 10, 3, 1, 1, 5, 1, 1, 1, 5, 2, 1, 1, 10, 5, 1, 1, 5, 3, 1, 1, 5, 4, 1, ... ...
Bass's user avatar
  • 77.4k
7 votes
1 answer
328 views

Fill The grid - 3.0

Can you fill this grid ? Version ($\pi$) In text: ?14516 243748 120581 17186? 01?857 HINT 1 HINT 2 HINT 3
19aksh's user avatar
  • 3,933
6 votes
1 answer
238 views

An ad-hoc number sequence to solve

Inspired by another question here, I thought I might create my own: Fill in the correct number in this sequence: 5, 3, 4, 9, 8, 3, 5, ... And of course, explain why :)
youcantryreachingme's user avatar
5 votes
1 answer
556 views

Next number sequence

Be forewarned: this is a riddle in the spirit of riddles. Given the following: ...4522222222255555555599999999 What are the next digits? Note: I did not specify the number of digits you should ...
justme's user avatar
  • 131
4 votes
1 answer
1k views

The "Slightly Spooky Sequence" Game

Two players, Alice and Beatrice, having previously agreed on a positive integer N (say 30) as a limit, take turns to write a sequence of positive integers. In the first turn Alice writes 1. Thereafter,...
Bernardo Recamán Santos's user avatar
4 votes
1 answer
584 views

The Generic Number Sequence Puzzle

If you are in a hurry, you can skip the story below, there's a TL;DR near the end. The gist is that we are going to solve every number-sequence puzzle ever*, all in one go. *: Terms and ...
Bass's user avatar
  • 77.4k
4 votes
2 answers
290 views

Yet another batch of four sequence puzzles

This is my sixth batch of sequence puzzles that are nasty and hard to solve; yet, each of them has a clear and justifiable solution. Sequence 1: Ca, Cl, ??, Er, ??, Po, Te, Th, ?? Sequence ...
Alexis's user avatar
  • 8,302
4 votes
3 answers
1k views

A simple but most devious sequence puzzle

This is a question from a previous, now-defunct version of the Temple of Quetzalcoatl, that I've posted here as an exemplar of one of the difficult puzzles you might encounter while solving it. The ...
user avatar
4 votes
2 answers
41k views

Not the usual "8 5 4 9 1 7 6 3 2 0" sequence puzzle

This is not the usual $8, 5, 4, 9, 1, 7, 6, 3, 2, 0$ sequence puzzle, which the answer of the pattern is The sequence is: $3, 9, 1, 5, 7, 0, 2, 4, 8, 6$. Can you figure the pattern of this sequence?
u-ndefined's user avatar
  • 5,181
4 votes
1 answer
377 views

Number Sequence Series-Question 2

I want to share a question that is created by myself. I will give a hint in 24 hours and my answer in 3 days given that nobody could answer my question. Here is my number sequence: 1441,2882,5764,?,...
LETTERKING's user avatar
4 votes
1 answer
172 views

Fill the grid - 2.0

Can you fill this grid ? (Version 2.0 ) Text version 714523 191303 165088 213443 573211 91?12?
19aksh's user avatar
  • 3,933
4 votes
0 answers
828 views

Number Sequence Series-Question 7

This is a series of questions that are created by me. Here is question 7: (23),(55),(155),(1255),?,?,(56139611) I will give a hint to you guys in one month if nobody can solve it.
LETTERKING's user avatar