Linked Questions

85 votes
222 answers
17k views

Sum of all integers from 1 to n

I'm honestly surprised that this hasn't been done already. If you can find an existing thread, by all means mark this as a duplicate or let me know. Input Your input is in the form of any positive ...
Gareth's user avatar
  • 1,299
50 votes
92 answers
8k views

Is this number a factorial?

The Task Given a natural number as input, your task is to output a truthy or falsey value based on whether the input is a factorial of any natural number. You can assume that the input number will ...
Arjun's user avatar
  • 5,074
52 votes
81 answers
7k views

It's Hip to be Square

Challenge So, um, it seems that, while we have plenty of challenges that work with square numbers or numbers of other shapes, we don't have one that simply asks: Given an integer ...
Shaggy's user avatar
  • 42.1k
49 votes
71 answers
7k views

An abundance of integers!

An Abundant number is any number where the sum of its proper divisors is greater than the original number. For example, the proper divisors of 12 are: ...
DJMcMayhem's user avatar
  • 59.3k
62 votes
44 answers
14k views

Find the Smoothest Number

Your challenge is to find the smoothest number over a given range. In other words, find the number whose greatest prime factor is the smallest. A smooth number is one whose largest prime factor is ...
isaacg's user avatar
  • 42k
19 votes
31 answers
2k views

Is this number tetrahedral?

Happy New Year 2024! 2024 is a tetrahedral number. A tetrahedral number is a number that can be represented in the form \$n(n+1)(n+2)/6\$ for some positive integer \$n\$. Or, equivalently, they are ...
alephalpha's user avatar
  • 48.5k
33 votes
7 answers
6k views

Match strings whose length is a fourth power

Within the scope of this question, let us consider only strings which consist of the character x repeated arbitrary number of times. For example: ...
n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳'s user avatar
11 votes
17 answers
841 views

Triangle and/or Square? [duplicate]

Explanation of the challenge Given an input, return what shapes it could be. There are only a couple options. Square Triangle Square A square is in the following format: ...
Neil's user avatar
  • 2,525
16 votes
8 answers
1k views

Decompose a number into triangles

Given an integer n, decompose it into a sum of maximal triangular numbers (where Tm represents the mth triangular number, or the sum of the integers from 1 to m) as follows: while n > 0, find the ...
Doorknob's user avatar
  • 71.5k
12 votes
9 answers
1k views

Polygonal Numbers!

Introduction In mathematics, a polygonal number is a number represented as dots or pebbles arranged in the shape of a regular polygon. The dots are thought of as alphas (units). These are one type ...
Oliver Ni's user avatar
  • 10.6k