A156779 a(n) = Sum_{d|n} sp(d), where sp(d) = A034387(d) = sum of primes <= d.

0, 2, 5, 7, 10, 17, 17, 24, 22, 29, 28, 50, 41, 60, 56, 65, 58, 92, 77, 111, 99, 107, 100, 167, 110, 143, 122, 165, 129, 214, 160, 225, 193, 220, 187, 285, 197, 276, 243, 325, 238, 390, 281, 393, 354, 383, 328, 536, 345, 457, 391, 476, 381, 573, 419, 563, 463

Offset

1,2

Links

Table of n, a(n) for n=1..57.

Mathematica

With[{max = 60}, sp = Accumulate[Array[# * Boole@PrimeQ[#]&, max]]; a[n_] := DivisorSum[n, sp[[#]] &]; Array[a, max]] (* Amiram Eldar, Aug 22 2023 *)

Prog

(PARI) vector(80, n, sumdiv(n, d, sum(i=1, primepi(d), prime(i))))

Crossrefs

Cf. A034387.

Sequence in context: A266594 A103871 A068817 * A345127 A226813 A355846

Adjacent sequences: A156776 A156777 A156778 * A156780 A156781 A156782

Keyword

nonn

Author

M. F. Hasler, Feb 21 2009

Status

approved