Forbidden integer ratios of consecutive power sums

Abstract

Let $S_k(m):=1^k+2^k+\cdots+(m-1)^k$ denote a power sum. In 2011 Bernd Kellner formulated the conjecture that for $m\ge 4$ the ratio $S_k(m+1)/S_k(m)$ of two consecutive power sums is never an integer. We will develop some techniques that allow one to exclude many integers $ρ$ as a ratio and combine them to exclude the integers $3\le ρ\le 1501$ and, assuming a conjecture on irregular primes to be true, a set of density $1$ of ratios $ρ$. To exclude a ratio $ρ$ one has to show that the Erdős-Moser type equation $(ρ-1)S_k(m)=m^k$ has no non-trivial solutions.