MathDB
2013 PUMaC Number Theory B4

Source:

November 24, 2013
modular arithmetic

Problem Statement

Compute the smallest integer n4n\geq 4 such that (n4)\textstyle\binom n4 ends in 44 or more zeroes (i.e. the rightmost four digits of (n4)\textstyle\binom n4 are 00000000).