A144489 Partial sums of A087624.

0, 0, 0, 1, 1, 3, 3, 4, 5, 7, 7, 9, 9, 11, 13, 14, 14, 16, 16, 18, 20, 22, 22, 24, 25, 27, 28, 30, 30, 33, 33, 34, 36, 38, 40, 42, 42, 44, 46, 48, 48, 51, 51, 53, 55, 57, 57, 59, 60, 62, 64, 66, 66, 68, 70, 72, 74, 76, 76, 79, 79, 81, 83, 84, 86, 89, 89, 91, 93, 96, 96, 98, 98, 100, 102

Offset

1,6

Comments

Number of pairs (p,q) with 1 < p < q <= n, p|q and p prime. - Wesley Ivan Hurt, Oct 30 2022

Links

Table of n, a(n) for n=1..75.

Mathematica

Accumulate[Array[If[PrimeQ[#], 0, PrimeNu[#]]&, 110]] (* Harvey P. Dale, Jul 19 2019 *)

Prog

(PARI) a(n) = sum(k=1, n, if (!isprime(k), omega(k))); \\ Michel Marcus, Nov 06 2022

Crossrefs

Cf. A002541, A087624.

Sequence in context: A104804 A240207 A347286 * A239640 A100091 A239483

Adjacent sequences: A144486 A144487 A144488 * A144490 A144491 A144492

Keyword

nonn

Author

N. J. A. Sloane, Dec 11 2008

Status

approved