Skip to main content

Unanswered Questions

21 questions with no upvoted or accepted answers
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 ...
6 votes
0 answers
254 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
302 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
265 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(...
4 votes
0 answers
333 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?
4 votes
0 answers
234 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 ...
4 votes
1 answer
561 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
660 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
156 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
171 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, ...
3 votes
0 answers
453 views

Logical descriptions of logic puzzles

What notations are there to describe a logic puzzle format? Here, I'm talking about logic puzzles like Sudoku, Bridges, Kakuro, Tents; games with exact rules and an exact & finite number of ...
3 votes
0 answers
959 views

A deciphering riddle

Recently in class a computer science related deciphering riddle was shown which I could not solve. For the course itself it is not obligatory to solve it but I am interested in the topic and I wonder ...
2 votes
0 answers
164 views

Sequence of shapes with lines and dot

This is another puzzle from Lanrt-F IQ test that was posted on Reddit https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd.it%2Fmy-favourite-2-problems-from-lanrt-f-v0-58puclks5a6d1.png%3Fwidth%...
2 votes
0 answers
318 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, ...
1 vote
0 answers
114 views

Can you find the missing letters?

A pattern of letters has had letters 10 through 20 deleted. Your job is to find out what letters should go in spots 10-20. Here is the pattern: a, b, c, d, d, d, f, e, f, _, _, _, _, _, _, _, _, _, _, ...

15 30 50 per page