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# 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]

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### 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 ...
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### 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
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### My dead mom left behind some number code

Background: I actually do not know the answer to this puzzle, but can answer any questions you may have. My mom who is now deceased had this series of numbers written in her notebook, that don't seem ...
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### What makes an Interesting Puzzle™?

This puzzle is based off the What is a Word™ and What is a Phrase™ series started by JLee and their spin-off What is a Number™ series. I like What is an Adjective Noun™ puzzles. Here are a few I ...
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### What comes next in the sequence? (Counting sheep)

My roommate has insomnia so he was counting sheep to help him sleep. He started with 2986, then continued with 47786, 764586, and 12233386. What sequence is he following, and what was the next number?
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### It's my birthday

Just like last year, my age is a number you can score with one dart. The year before that, it wasn't, and it won't be next year. How old am I?
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### A very simple puzzle: 1,1,2,1,2,2,3

Here's a simple puzzle, I know that you will find. As long as you can count, It shouldn't take much time. 1 1 2 1 2 2 3 1 2 2 3 Find the next 4 numbers in this sequence.
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### What is the next number in the series: 21, 21, 23, 20, 5, 25, 31, 24,?

I came across a puzzle from a workbook for primary school students who wish to sit in exams for enrolling to selective high schools, which asks about what is the next number in the series. What is ...
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### A powerful drink

I'm addicted to this stuff. I had my first double when I was 16. There were five of us that night on the town. I didn't think much of it then, but two years later I had another double, and then ...
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### An unusual and very hard number sequence problem

I heard this number sequence problem about 25 years ago from a maths lecturer. What number should go in the place of the question mark in this mathematical sequence: ..., 30, ?, 60, 90, 140, 225, 372, ...
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### Professor Halfbrain and the sum of the digits of all divisors

Yesterday I met professor Halfbrain in the city. The professor looked tired and somewhat exhausted. He told me that he had spent his nights and days with adding up digits of divisors of positive ...
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### Ancient machine in the desert... how does it generate its output?

I was walking through the desert and came across an ancient contraption of cogs and gears. It had a series of dials on one side that appeared to allow the input and output of numbers. On the other ...
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### That gap is a bit jarring

... but there doesn't seem to be anything missing. $0,1,2,3,4,5,6,7,1527465$ What then could cause that rather large gap?
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### 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 ...
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### Why aren't the numbers playing nicely anymore?

The natural numbers have gotten in a big fight and split up into groups. If we can't get them back together again, the universe may never be the same! What kind of sense does it make to have three ...
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### 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 ...
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### 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 ...
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### A predictable sequence

"Four, four, four, ..." droned the random number generating monster. "Are you sure that's random?" I asked. "That's the problem with randomness, you can never be sure!" ...
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### A brief int counter

The following infinite sequence is used by those taking first steps in maths. 3, 3, 4, 4, 4, 3, 4, 5, 3, 3, 4, 5, 6, 7, ? Find the next number.
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### 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 ...
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### 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! ...
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### Revenge on OEIS*

First, a story about how I messed up a puzzle: It’s hard to make a simple yet creative number puzzle. After fiddling one late, dark winter evening with different patterns, at last I made a sequence ...
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### What is a RAP Number™?

Taking inspiration from "What is the word™" series, here the numbers conforms to a special rule, I call it a RAP number™. Use the following examples below to find the rule. Note : This is my first ...
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### Ernie and the Alien Invasion

Yesterday I dropped in on Ernie to show off my new j-watch. Ernie wouldn't be impressed by instant wrist-mounted access to social media sites like me-tube, tweeter and farce-book so I thought I would ...
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### A real time-waster: the clock of confusion and color

John was doing his math problems like a good child one day until he looked at the clock to see if it was time to sleep. To his dismay, the blasted thing had become another math problem! But this one ...
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### What kind of puzzle is solved by these sequences of numbers?

Samantha had been fiddling with something at her desk for ages, and constantly scribbling notes on a piece of paper. When my curiosity eventually got the better of me, I wandered over to ask what she ...
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### A riddle that has been killing me the whole day

So I'm walking around in London and found the following number riddle. The rules say, that what ever pattern you find, must be true for the rows as well as the columns. The answer in level 1 is for ...
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### REALLY important days in history

@Z. Dailey asks a mathematical puzzle Important days in history... and to come! with a series of dates in years 1973, 1978, 1983, 1992, 2005. My puzzle asks the question: What is the previous date in ...
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### How does this addition work (13+7=1130)?

I found this problem on 9gag and I have no idea how to solve it. Here is the question: $13+7=1130$ $88+9=47$ $32+28=2530$ $10+999=1149$ $444+77=61$ $55+111=56$ $21+0=1221$ $7+22=39$ $33+5=38$...
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### Describe your ability to solve this number sequence!

Here is a sequence of numbers: 0, 2, 4, 6, 8, -, -, -, 10, 12 Can you fill in the three blanks and thus reveal your excellent puzzle-solving ability?
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### What is the last integer in this sequence?

Here are the first several entries in a finite sequence of integers. $$31, 45, 71, 89, 91, 94, 111, 112, 118, 121, 126, 131,$$ $$134, 135, 139, 143, 144, 145, 148, 158, 161, 189, 193, 194, \dots$$ ...
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### What does this group of numbers represent?

How is this set of 8 numbers - $6, 8, 15, 20, 36, 48, 90$, and $120$ - derived? I could provide hints but it would make it too easy.
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This puzzle is part of the Monthly Topic Challenge #2: IQ Puzzle Parody Can you find out the next one in the sequence, how it's different to the ones before it, and explain the pattern? 1 10 11 20 31 ...
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### How is this number sequence built up and how does it continue?

Can you work out how this number sequence is built up? Can you work out how it continues? 1, 1, 2, 4, 8, 20, 60, 240, 1500, ....... Hint 1 Hint 2 From time to time hints will be updated. Note: ...
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### A geometric sequence using one digit

Give the first few terms of a geometric[1] sequence such that: the sequence is increasing and infinite only one digit is used throughout the sequence the terms are written as base ten ...
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### 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:
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### Quality Over Quantities

Your final answer will be a number (or maybe not?) 6.1482925535194332784626433, 15, 70, 5388440228181184467208035634811703511875, 45, 1207432478148385373947988/38313917, 15, 70, ?
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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 \\ ...
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### Some enigmatic number sequences

Here are some numbers: 959, 233, 14, 36, 105, 45, 784, 120, 1579, 1001, 1111, 90, 841, 1607, 590, 625, 609, 144, 606 And here are the rest of the numbers: 1, 2, 5, 20, 30, 34, 42, 55, 56, 66, 72, 78, ...
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### Rethinking this series on the syllabus

I assigned each person in my class the task of creating a number-sequence, however, 4 of the guys I usually consider to be leaders came back with baffling results. Can you make sense of their work and ...
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### Creepy video on Youtube, with secret cipher built in

This showed up in r/deepintoyoutube: https://www.youtube.com/watch?v=j1ExfbH4Jew I've posted it around, and no one has solved it. I believe it is a cipher for a couple of reasons, at the end 26 ...
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### 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 ...
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### 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 ...
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### Find d this ones stumped me help?

This one is annoying me so much. Got this from a maths teacher.
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### What is the next number in the series?

What is the next number of this series? 1 , 4 , 5 , 6 , 7 , 9 , 11 ?
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### Mathematical cryptic clues

Programming language, after removing loss for you, reverses time (6) Complex arithmetic begins, Turing tests start beforehand (7) Quadruply male doctor Einstein, familiarly (11) Lie on a ...
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### Can you find O in this math riddle?

If: R = 1,111 T = 2,222 E = 3,333 N = 4,444 What is O equal to?
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### Sequence puzzle

This is a sequence puzzle I found online which I'm stuck on: 452801, 773924, 102410, 471056, ? I figured out how to get from the first number to the second (+3, +2, +1, +1, +2, +3) for the digits, ...
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### Given these numbers, find the secret word

My son is 12 years old and his task was to find an English word from these numbers: 13; -8; 2; 2; -6; 12; 2; 6; -1; -12 where ...
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