MathDB
Classical NT about density of numbers of a special form

Source: Bulgaria MO Regional round 2024, 12.4

February 13, 2024
number theory

Problem Statement

Find all pairs of positive integers (n,k)(n, k) such that all sufficiently large odd positive integers mm are representable as m=a1n2+a2(n+1)2++ak(n+k1)2+ak+1(n+k)2m=a_1^{n^2}+a_2^{(n+1)^2}+\ldots+a_k^{(n+k-1)^2}+a_{k+1}^{(n+k)^2} for some non-negative integers a1,a2,,ak+1a_1, a_2, \ldots, a_{k+1}.