A345278 a(n) = Sum_{p|n} p^(pi(p) mod 2).

0, 2, 1, 2, 5, 3, 1, 2, 1, 7, 11, 3, 1, 3, 6, 2, 17, 3, 1, 7, 2, 13, 23, 3, 5, 3, 1, 3, 1, 8, 31, 2, 12, 19, 6, 3, 1, 3, 2, 7, 41, 4, 1, 13, 6, 25, 47, 3, 1, 7, 18, 3, 1, 3, 16, 3, 2, 3, 59, 8, 1, 33, 2, 2, 6, 14, 67, 19, 24, 8, 1, 3, 73, 3, 6, 3, 12, 4, 1, 7, 1, 43, 83, 4, 22, 3

Offset

1,2

Links

Table of n, a(n) for n=1..86.

Example

a(15) = Sum_{p|15} p^(pi(p) mod 2) = 3^0 + 5^1 = 6.

Mathematica

Table[Sum[k^Mod[PrimePi[k], 2] (PrimePi[k] - PrimePi[k - 1]) (1 - Ceiling[n/k] + Floor[n/k]), {k, n}], {n, 100}]

Crossrefs

Cf. A000720 (pi), A345279.

Sequence in context: A216913 A124218 A025165 * A212431 A346517 A318354

Adjacent sequences: A345275 A345276 A345277 * A345279 A345280 A345281

Keyword

nonn

Author

Wesley Ivan Hurt, Jun 12 2021

Status

approved