Question 18
How many positive integers n less than 100 are there such that $n!$ is divisible by the sum of the first n positive integers?
Note: $n!=1\times2\times\cdots\times(n-1)\times n$.
Note: $n!=1\times2\times\cdots\times(n-1)\times n$.
IMSO Maths · IMSO 2022 Mathematics — International Short Answer