MathDB
Divisors

Source: 2014 Czech & Slovak Mathematical Olympiad, Rnd. III, Cat. A

May 20, 2014
modular arithmeticnumber theory unsolvednumber theory

Problem Statement

Let be nn a positive integer. Denote all its (positive) divisors as 1=d1<d2<<dk1<dk=n1=d_1<d_2<\cdots<d_{k-1}<d_k=n. Find all values of nn satisfying d5d3=50d_5-d_3=50 and 11d5+8d7=3n11d_5+8d_7=3n.
(Day 1, 1st problem author: Matúš Harminc)