Questions tagged [number-sequence]

A puzzle that asks for the pattern in a given number sequence.

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49
votes
4answers
8k 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
25
votes
1answer
2k 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 ...
4
votes
1answer
349 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. ...
6
votes
8answers
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 ...
13
votes
1answer
480 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 ...
3
votes
1answer
1k 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 ...
55
votes
1answer
3k 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 ...
1
vote
2answers
3k 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 ...
-1
votes
3answers
979 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 ...
-2
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1answer
5k 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, ?
22
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1answer
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 ...
25
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2answers
20k 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 ...
10
votes
3answers
559 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,\...
10
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2answers
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...
7
votes
1answer
383 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 ...
1
vote
3answers
580 views

What is the next number in the following sequence?

1, 6, 5, 3, 4, 1, 2, 2, ? Hint: the task is pattern recognition using basic mathematical operations.
17
votes
2answers
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 \\ ...
15
votes
9answers
3k 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 ...
24
votes
1answer
778 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 ...
13
votes
1answer
505 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 ?
10
votes
6answers
812 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 ...
10
votes
2answers
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 ...
3
votes
0answers
597 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.
16
votes
5answers
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 ...
15
votes
5answers
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 ...
12
votes
3answers
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. ...
8
votes
2answers
425 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 ...
3
votes
1answer
1k views

Alphabet Number Matching

If : 888888 = T 777777 = O 555555 = Y 444444 = R then : 666666 = ? Basically you need to tell the logic along with ...
2
votes
1answer
143 views

Number Sequence Series-Question 3

I want to share a series of questions that are 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: 2020,...
4
votes
3answers
976 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 ...
3
votes
1answer
301 views

Another mathematical number sequence

Can you work out the mathematical rule for this number sequence? 354, 72, 345, 132, 6, 216, 9, 729, 354, 72, 345........ Hint 1 From time to time hints will be updated until solved. Note: this ...
14
votes
2answers
715 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) ...
12
votes
1answer
1k 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,...
10
votes
3answers
661 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•...
9
votes
1answer
339 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 ...
8
votes
1answer
747 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 ...
4
votes
1answer
394 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 ...
0
votes
1answer
377 views

A final batch of four sequence puzzles

This is my seventh (and probably last) batch of sequence puzzles that are nasty and hard to solve; I stress that each of them has a clear and justifiable solution. Sequence 1: RC, NU, RT, RS, PI, ...
-4
votes
10answers
921 views

SafeCracker #3 - We've Been Blocked [closed]

Our Last Safe To Conquer Ok, team, this one might give us a little trouble. Nothing we can't handle though... let's go... This safe model is "The NevaCrak 9000" - the most secure safe there is. ...
-7
votes
2answers
366 views

Next number in the following sequence? [closed]

In following sequence, Find the next number? 85, 79, 73, 69, ?
9
votes
1answer
746 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 ...
8
votes
2answers
737 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, ... ...
7
votes
1answer
306 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
6
votes
1answer
205 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 :)
5
votes
1answer
141 views

Fill the grid - 2.0

Can you fill this grid ? (Version 2.0 ) Text version 714523 191303 165088 213443 573211 91?12?
5
votes
1answer
435 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 ...
4
votes
2answers
252 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 ...
4
votes
3answers
308 views

Number Sequence Series – Question 1

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: $3/2, 2/3, 3/4, ...
4
votes
2answers
236 views

Two honeycomb hints, part two (find the next number)

Another variant of my previous question, this one might be easier (or harder). What is the next number in the sequence $1, 2,6, 16, ...$? To clarify: the 'hints' are really clues. They are hidden, ...
4
votes
1answer
275 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,?,...