The sum of powers of even divisors of a number. It is the analog of the divisor function for even divisors only and is written σ_k^(e)(n). It is given simply in terms of the usual divisor function by σ_k^(e)(n) = {0 | for n odd 2^k σ_k(n/2) | for n even. auto right match

divisor function | odd divisor function