A369745 a(n) = Sum_{p|n, p prime} p * pi(n/p).

0, 0, 0, 2, 0, 7, 0, 4, 6, 11, 0, 12, 0, 15, 19, 8, 0, 17, 0, 18, 26, 21, 0, 22, 15, 25, 12, 26, 0, 39, 0, 12, 37, 31, 41, 29, 0, 35, 44, 36, 0, 55, 0, 38, 38, 41, 0, 36, 28, 38, 55, 44, 0, 39, 58, 46, 62, 49, 0, 69, 0, 53, 52, 22, 69, 79, 0, 56, 73, 80, 0, 49, 0, 61

Offset

1,4

Links

Table of n, a(n) for n=1..74.

Formula

a(p^k) = p * pi(p^(k-1)), for p prime and k >= 1. - Wesley Ivan Hurt, Jun 26 2024

Mathematica

Table[DivisorSum[n, #*PrimePi[n/#] &, PrimeQ[#] &], {n, 100}]

Crossrefs

Cf. A000720 (pi), A066328.

Sequence in context: A291373 A342700 A021487 * A197391 A340367 A340197

Adjacent sequences: A369742 A369743 A369744 * A369746 A369747 A369748

Keyword

nonn,easy

Author

Wesley Ivan Hurt, Jan 30 2024

Status

approved