Numbers k such that Sum_{j=1..k} sigma_*(j) == 0 (mod k), where sigma_*(j) is the sum of the anti-divisors of j (A066417).

A229883

Numbers k such that Sum_{j=1..k} sigma_*(j) == 0 (mod k), where sigma_*(j) is the sum of the anti-divisors of j (A066417).