A369913 a(n) = Sum_{p|n, p prime} n^sopf(n/p).
0, 1, 1, 16, 1, 252, 1, 64, 729, 100100, 1, 248976, 1, 105413700, 762750, 256, 1, 1895400, 1, 1280000400, 1801097802, 584318301411812, 1, 7963200, 9765625, 2481152873203737252, 19683, 10578455954192, 1, 677994300000, 1, 1024, 50542106513762754
Offset: 1
Programs
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Mathematica
a[n_] := Sum[p, {p, Select[Divisors[n], PrimeQ]}]; Table[DivisorSum[n, n^a[n/#] &, PrimeQ[#] &], {n, 40}]
Formula
a(p^k) = p^(p*(k-floor(1/k))) for p prime and k>=1. - Wesley Ivan Hurt, Jul 09 2025
Comments