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Questions tagged [sequence]

A puzzle about a series or collection of symbols, elements, or other objects, whose chosen ordering obeys a specific logical rule, which is usually to be determined.

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93 votes
7 answers
18k views

Thanks, dad! Never again

No idea why my dad dragged me into this place. Some guy is performing on the stage. He's reading numbers out loud. I think it's some kind of a sequence puzzle. 1... 8... 9... 16... 17... ...
Jafe's user avatar
  • 77.2k
40 votes
3 answers
2k views

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?
DenverCoder1's user avatar
  • 10.5k
33 votes
1 answer
3k views

The mystery flag

Part two - The mystery flag - twisted Based on these flags: (Count the sun in the Argentina flag as yellow) Which country does this flag belong to? Please explain why EDIT: I added a black ...
Beastly Gerbil's user avatar
32 votes
3 answers
2k views

Should You Take the Pill?

An entry in Fortnightly Topic Challenge #50: Escape Rooms Your head is throbbing like mad. You try to get your bearings as you look around the laboratory. Shattered beakers and spilled chemicals are ...
Amoz's user avatar
  • 27.1k
29 votes
12 answers
2k views

Shapes and letters. What is the missing box?

Finally, someone has figured it out. Good job.
Rudy Matunic's user avatar
24 votes
1 answer
1k views

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!" ...
Matt's user avatar
  • 1,711
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
23 votes
1 answer
699 views

Sergeant Sequence takes the case

It was 2am and Sergeant Sequence had been called in to Headquarters urgently. The second he stepped through the door a file was pressed into his hands by the Chief Investigator, who began to talk ...
Stiv's user avatar
  • 144k
22 votes
5 answers
2k views

There are fifteen triangles, what is the sixteenth?

This is "fifteen triangles": ▲ ▼ ▲ ▲ ▼ ▼ ▲ ▲ ▲ ▼ ▼ ▲ ▲ ▲ ▼ ? Each triangle points up or down. What the "?" figure should be and why?
enkryptor's user avatar
  • 323
22 votes
0 answers
2k views

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 ...
Haobin's user avatar
  • 11.7k
20 votes
1 answer
2k views

Can One Solve This Scary Sequence?

The following terms appear in a sequence. Unfortunately, they are scrambled (both the original terms and their order). Theory, Policeman?, Contest, Clarice, Bad Act, One in Rome, Fashionable, Confess,...
AlteringIntegral's user avatar
20 votes
1 answer
792 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
20 votes
1 answer
2k views

Only Connect - all at once!

This puzzle is part of the Monthly Topic Challenge #9: Game/Quiz Shows. Did you see the glitch on Only Connect last Monday?* The one where all four of the rounds got merged into one?! Effectively, ...
Stiv's user avatar
  • 144k
20 votes
1 answer
934 views

rectangles gone black

Based on the sequence of rectangles you see below, which rectangle (A-E) should replace the question mark? Once you figure out what this puzzle is all about you'll know which of the five should ...
Prim3numbah's user avatar
19 votes
1 answer
537 views

Almighty threats!

There's rhyme and reason behind the following 10-step sequence of words and phrases: 1. HUSK 2. BE COMELY 3. TRACKED 4. NOT HOOK 5. KICK TIPS 6. CUSP 7. ALMIGHTY 8. THREATS 9. BEFIT 10. ? The name ...
Stiv's user avatar
  • 144k
19 votes
1 answer
701 views

Chain Puzzle: Tabletop Games #01 - Let's Play

This is the first Chain Puzzle in the Tabletop Games series, in which all puzzles are themed around board games, card games, tile games, and the like. The answer to this puzzle is a thematic word or ...
Stiv's user avatar
  • 144k
18 votes
1 answer
624 views

A fortified nonogram

This puzzle is part 21 of Gladys' journey across the globe. Each part can be solved independently. Nevertheless, if you are new to the series, feel free to start at the beginning: Introducing Gladys. ...
Jafe's user avatar
  • 77.2k
18 votes
1 answer
650 views

PSE Advent Calendar 2022 (Day 4): Letters to Father Christmas (Sgt. Sequence Fan-Fic)

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 100 reputation.< Previous DoorNext Door > "Good ...
Jeremy Dover's user avatar
  • 28.3k
17 votes
1 answer
1k views

A week around Europe

I've recently returned from a week of travelling around Europe, visiting a different town or city in a different country on each day, choosing my destinations according to an underlying pattern. I've ...
Stiv's user avatar
  • 144k
17 votes
2 answers
938 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
17 votes
1 answer
785 views

You can count on Sergeant Sequence

"Ah, Sequence, there you are," said the Chief Investigator as Sergeant Sequence entered the briefing room. "Your man Patrick Terne is on the move again, and we need your help to track ...
Stiv's user avatar
  • 144k
17 votes
3 answers
677 views

Basically Binary but Boldly Baffling

Another image sequence puzzle inspired by @Conifers, enjoy ;D Colorblind-friendly version Clarification: one or more tag(s) has been deliberately omitted to enhance the difficulty. Hints 1 2a 2b ...
Omega Krypton's user avatar
16 votes
1 answer
4k views

Radical IQ challenge

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 ...
PuzzlingFerret's user avatar
16 votes
2 answers
2k views

What is the next number in the series?

What is the next number of this series? 1 , 4 , 5 , 6 , 7 , 9 , 11 ?
Ram Visagan's user avatar
16 votes
2 answers
983 views

Sergeant Sequence brings in the analysts

This puzzle is part of the Monthly Topic Challenge #5: On-and-onograms "We've intercepted another message, Chief." "Good work, Sequence. What does it say? Where is Terne now?" The ...
Stiv's user avatar
  • 144k
16 votes
2 answers
1k views

What should we put in the 6th box?

Below there is a small sequence. What should we put in the 6th box?
Lezzup's user avatar
  • 6,012
16 votes
1 answer
2k views

Can you solve this Country puzzle?

Given this sequence of flags, which flag should replace the question mark? Explain. Note: I added 'knowledge'-tag, but it's nothing complicated.
Prim3numbah's user avatar
16 votes
1 answer
2k views

This won't work with US states

This puzzle is part of the Monthly Topic Challenge #12: mobile-friendly puzzles. For each of the following sequences, identify the three missing terms (marked by '???'): Nitrogen, Fluorine, Argon, ...
Stiv's user avatar
  • 144k
16 votes
1 answer
383 views

Chess A Knight's Journey

You'll need to know about: A game that has existed for over 1500 years A game that doesn't exist ♞ → I → II → III → ... Answer = Xxxxxxxxx
EnzoSansaloni's user avatar
15 votes
1 answer
2k views

A strange number pattern, isn't it?

This looks like a strange number sequence to me. Or is it? 1 2 3 4 5 6 7 8 9 10 12 13 14 15 16 17 18 20 21 22 23 24 25 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 ? ? ? ? ? So what are ...
DrD's user avatar
  • 39.3k
15 votes
1 answer
1k views

Sergeant Sequence faces his toughest (IQ) test yet

This puzzle is part of the Monthly Topic Challenge #2: IQ Puzzle Parody Lando had never felt so nervous. The Badger and Biscuit's 'KWIZ NITE' was only minutes away from starting, and he had just ...
Stiv's user avatar
  • 144k
15 votes
1 answer
915 views

E Rebus Unum – a picture sequence puzzle

This is part 42 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Dear Puzzling, Today I have been taking it easy. You might even say it has been a walk in the ...
Jafe's user avatar
  • 77.2k
15 votes
1 answer
471 views

Spot the pattern. There is none

Look at these pictures: What's the next picture? As requested, bellow is a set of possible answers. You don't have to look at them to find the correct answer.
Reinis Mazeiks's user avatar
14 votes
2 answers
2k views

4,4,2,6,2,10,4,_ sequence from 4th grade packet

The sequence (from my child's "for fun" challenge packet, not for credit or graded) is: 4,4,2,6,2,10,4,_ The possible answers are: A) 15 B) 20 C) 25 D) 28
jmcarson's user avatar
  • 243
14 votes
2 answers
2k views

Modification of 100 lightbulbs problem (everyone flips 100 bulbs each)

This is a modification to the usual 100 lightbulbs in a room puzzle. Like before, the first person flips the switch of every lightbulb. However, while the second person also starts from the first ...
Ice Tea's user avatar
  • 309
14 votes
7 answers
8k views

IQ-test-type question - sequence of large triangles with black and white small triangles in them

This puzzle is said to be from a Russian test and has an obvious but not fully fitting answer: The task is to find correct picture to replace question mark. The "obvious" pattern is But of ...
klm123's user avatar
  • 16.2k
14 votes
1 answer
1k views

A Harry Potter sequence puzzle

What is the next term in the following sequence based on Harry Potter? None, 16, None, 16, 5, 9, ?
Raziman T V's user avatar
  • 2,448
14 votes
2 answers
390 views

It comes full circle

Top, Middle, Bottom, Double-Right; Double-Right; Up Left, Middle, Double-Right; Double-Right; Top, Middle, Bottom, Up Left, Down Right; Top, Middle, Bottom, Up Left, Double-Right; ??? What would ...
Chowzen's user avatar
  • 25.7k
14 votes
2 answers
427 views

Sergeant Sequence leads the way

Sergeant Sequence entered the Chief Investigator's office to find his boss in some agitation. "Patrick Terne is on the move again, Sequence," sighed the Chief, "and once more I find ...
Stiv's user avatar
  • 144k
14 votes
1 answer
808 views

What is the sequence?

The following 5 sequences of base-10 numbers all follow the same pattern, and converge at 14,. What is the pattern and which number is next? 1,5,10,14,23,... 2,6,10,14,23,... 3,9,14,23,... 4,9,14,23,.....
simonalexander2005's user avatar
14 votes
1 answer
753 views

We Need to Extract Frank’s Site Rankings

I asked my friend Frank to rank his favorite Stack Exchange sites from 1 (favorite) to 10 (least favorite). This is the feedback he left, but I got them a little mixed up and don’t know which he ...
Amoz's user avatar
  • 27.1k
14 votes
3 answers
384 views

Look at me - a number sequence

This sequence goes on forever, but here are the first 7 terms. The X's are just there to hide the actual digits. Can you find all the correct digits of the 8th entry? 1024, 90X1X, 25023X, 490364, ...
Prim3numbah's user avatar
14 votes
1 answer
2k views

Mom Got Me Shoes For My Birthday

What number must replace the question mark below? 218 19 780 17 11 9,000 301 6 8 600 ? 80 70
JLee's user avatar
  • 18.8k
13 votes
4 answers
598 views

This number sequence has entered my life recently

Just recently, I've noticed this sequence of numbers has become a pretty big part of my life. It goes like this: 1, 2, 4, 6, 9, 12 So here's the mystery: What is this sequence? Where do I keep seeing ...
AJFaraday's user avatar
  • 628
13 votes
1 answer
898 views

Twelve numbers omitted

This is the beginning of a simple sequence. NO Computers or special knowledge are required. Insert the missing numbers. Explain how the sequence was generated. Note: the line breaks can be ignored, ...
Amoz's user avatar
  • 27.1k
13 votes
1 answer
778 views

This puzzle is a loss

What should replace the question mark on this list? JBNRS, HF, GM, JPD, VL, AELMP, MS, WB, CB, GS, EC, SV, PD, PEJP, ?, … Hint, added later: Hint, added even later:
msh210's user avatar
  • 12.8k
13 votes
1 answer
472 views

The Very Model of a Number Sequence

Number sequence questions are normally not received well here but I thought this one might warrant a bit more attention as it has the following interesting properties: It is a finite sequence. Each ...
hexomino's user avatar
  • 136k
13 votes
2 answers
723 views

You don't want to sell me matchsticks

Fix the image before completing the sequence. What do I want you to draw your attention to? 103, 91, 79, 0, x, x, 28, x, x, x, 0, 78, x, x, x, x, x, x, 5 Hints:
Lukas Rotter's user avatar
  • 10.3k
13 votes
1 answer
424 views

A simple twist on a classic puzzle

Given this sequence: 0, 4, 84, 212, 1940, 358036, 14113428, 127377044 What is the next item? Hint: Hint:
MilesZew's user avatar
  • 689
12 votes
2 answers
642 views

Arithmetic-progression-free sequences

This question Sudokus with no 3-term arithmetic progressions within made me wonder about the following question. What is the longest sequence composed of the integers 1..N (or 0..N-1 if you have a ...
Florian F's user avatar
  • 30.1k

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