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
6 votes
0 answers
243 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 ...
6 votes
0 answers
296 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. ...
5 votes
0 answers
253 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
4 votes
0 answers
309 views

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
4 votes
0 answers
230 views

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 ...
• 8,653
4 votes
1 answer
549 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 ...
4 votes
1 answer
489 views

Find next element of the sequence

Source of the question: Taken from the sub-Reddit r/askmath here: https://www.reddit.com/r/askmath/comments/15ar3ne/looking_for_the_answer_to_the_following_sequence/ What is the next element of the ...
3 votes
0 answers
150 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: ...
3 votes
0 answers
167 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
2 votes
0 answers
303 views

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
0 answers
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 ...
• 8,653
1 vote
0 answers
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
0 answers
179 views

Find the next term in the given sequence

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:
• 1,573
-7 votes
1 answer
282 views

Find the next number in the weird sequence

The following sequence has been made using a specific pattern and the last number is kept secret. We have to find that number along with the pattern followed to make the sequence. 3, 11, 32, 71, 136, ...