A092347 a(0)=1; a(n) = sigma_1(n) + sigma_2(n) + sigma_3(n).

1, 3, 17, 42, 101, 158, 314, 402, 685, 861, 1282, 1466, 2282, 2382, 3370, 3812, 5053, 5222, 7307, 7242, 9786, 10164, 12634, 12722, 17290, 16433, 20674, 21300, 26218, 25262, 33124, 30786, 38877, 38564, 45730, 44692, 57263, 52062, 63610, 63300, 76010, 70646, 89284

Offset

0,2

Links

Amiram Eldar, Table of n, a(n) for n = 0..10000

Mathematica

a[0] = 1; a[n_] := Total[DivisorSigma[{1, 2, 3}, n]]; Array[a, 50, 0] (* Amiram Eldar, Dec 16 2024 *)

Prog

(PARI) a(n) = if(n == 0, 1, sum(k = 1, 3, sigma(n, k))); \\ Amiram Eldar, Dec 16 2024

Crossrefs

Cf. A000203, A001157, A001158.

Sequence in context: A135471 A322755 A226492 * A215429 A126587 A108126

Adjacent sequences: A092344 A092345 A092346 * A092348 A092349 A092350

Keyword

nonn,easy

Author

N. J. A. Sloane, Mar 20 2004

Status

approved