OFFSET
0,2
FORMULA
G.f.: 1 + Sum_{k>=1} k^2*(k + 1)*x^k/(1 - x^k). - Ilya Gutkovskiy, Mar 17 2017
MATHEMATICA
Join[{1}, Table[DivisorSigma[2, n]+DivisorSigma[3, n], {n, 50}]] (* Harvey P. Dale, Feb 05 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 20 2004
STATUS
approved