MathDB
Sum of remainders

Source: Iberoamerican Olympiad 2005

September 29, 2005
number theory solvednumber theory

Problem Statement

Denote by amodba \bmod b the remainder of the euclidean division of aa by bb. Determine all pairs of positive integers (a,p)(a,p) such that pp is prime and amodp+amod2p+amod3p+amod4p=a+p. a \bmod p + a\bmod 2p + a\bmod 3p + a\bmod 4p = a + p.