1801097802domain: NAppears in sequencesn^(p1) + n^(p2) + n^(p3) + ... where (p1)*(p2)*(p3)*.... is the prime factorization of n (with multiplicity).at n=20A239283a(n) = Sum_{p|n, p prime} n^p.at n=20A351365a(n) = Sum_{p|n, p prime} n^sopf(n/p).at n=20A369913