OFFSET
0,2
FORMULA
Sum_{k=1..n} a(k) ~ (17*zeta(4)/8) * n^4. - Amiram Eldar, Dec 12 2023
MATHEMATICA
Join[{1}, Table[DivisorSigma[3, n], {n, 2, 80, 2}]] (* Harvey P. Dale, Feb 26 2011 *)
PROG
(PARI) a(n) = if(n < 1, 1, sigma(2*n, 3)); \\ Amiram Eldar, Dec 12 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Mar 20 2004
STATUS
approved