# 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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### 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 ...
• 11.7k
243 views

### Mind your P's & Q's

Here is a numbered sequence of words/phrases. Where should SESQUIPEDALIAN fit in this list? ZIPPER PEPPER MONEY SNIPPY PRIMED PIPPED SNAPPED POUND PUPPY PARADROPPED QUASI-POPULAR PEOPLE ... (sequence ...
• 27.1k
248 views

### Sequence puzzle: 3, 9, 27

A twist of the classic sequence game: A friend asked me to find the rule to this sequence: 3, 9, 27. I am allowed to suggest other sequences to test if they follow that (unknown to me) rule, to which ...
300 views

### Find the missing element?

I've been trying to solve this for quite some time, can you help me solve it? This puzzle was made by one of my friend's teachers. This is not copyrighted and cannot be found anywhere on the internet. ...
258 views

### Longest Fibonacci word

Fibonacci words are defined as $F_0 = a, F_1 = b, F_{n+2} = F_nF_{n+1}$ where $a, b$ are letters. How can you find the longest Fibonacci sub-word in a given string? Try to solve it in linear time (\$O(...
• 151
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### Lucas's interesting cipher

Lucas was fooling around with some letters when he encoded some text into Gsobj lwmtkd sbceugb vfy rgdjb.. Can you figure out the original text he had?
• 439
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### The smallest number

Some time ago I created a program to generate a table, and printed the first seven rows and columns. Somehow however I forgot to print the headers and the title of the table. I only remember that it ...
• 9,178
552 views

### Formula for the sequence 1, 1, 1, 21, 3, 1, 4, 1, 5, 1, 6, ... if the 21 isn't a mistake

The sequence 1, 1, 1, 21, 3, 1, 4, 1, 5, 1, 6, ... appeared in one of my tutorial sheets in 2019. I assumed that the fourth term, 21, was a mistake (was supposed to be ..., 2, 1, ...) then it made ...
530 views

153 views

### The Mono-Quantum Condrum

You are presented with a locked box, and on its surface, you notice a sequence of peculiar symbols: ⌬ ⌅ ⊙ ⊡ Next to the symbols, there's an inscription: ...
168 views

### Odd one's out (sequence)

Once upon a time, there was a curious mathematician named Friedrich. One day, while exploring a new area of mathematics, he stumbled upon an intriguing sequence of numbers: 0, 1, 2, 2, 4, 3, 3, 4, 4, ...
• 31
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### What's the missing number related to primes?

I would like to draw your attention to this mathematical sequence related to prime numbers I've created and ask what the missing number is. 2, 5, 27, 182, 2310, 27200, ______, 8998400, 223092870, ...
• 29
1 vote
142 views

### An increasing decreasing sequence

In math, there are all kinds of sequences 1545, 1218, 1071, 921, 851, 832, 799, 793, 774, 745, ... is (the start of) such as sequence What is the best number? Note: Even in math things change, so ...
• 9,178
1 vote
208 views

### I need help deciphering what looks like a binary message

I was watching a YouTube video and it’s filled with secret messages and codes. The last two codes were in binary and inserting them into a translator provided correct answers. However, that's not ...
• 11
1 vote
I created this puzzle. The sequence is as follows: $$320, 71,4632,1E3D, 84B7, 6154, 4F3A44, 38B12, 11F1, BE7E44$$ Find the next element in the above sequence. Hint 1: Hint 2: Hint 3: Hint 4: