Grossman Math Olympiad, 2022, Seniors

• Question 1 - Sums of Factorials

  For every positive integer n, let us denote `n! = 1*2*3*...*n`

  Find all integers n such that the sum `1! + 2! + 3! + ... + n!` is the square of an integer.

  (Solution format: a,b,c,... i.e., the three smallest numbers separated by commas with no spaces, and three dots after if there are more solutions)

  Show hint

  Log in here to receive the hint
  Topics:

  Number Theory -> Modular Arithmetic / Remainder Arithmetic Algebra -> Sequences