OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
Dirichlet g.f.: zeta(s)*zeta(s-8)/zeta(2s-8). - R. J. Mathar, Apr 12 2011
If n = Product (p_j^k_j) then a(n) = Product (1 + p_j^(8*k_j)). - Ilya Gutkovskiy, Nov 04 2018
Sum_{k=1..n} a(k) ~ 10395*Zeta(9)*n^9 / Pi^10. - Vaclav Kotesovec, Feb 07 2019
MATHEMATICA
Table[Total[Select[Divisors[n], CoprimeQ[#, n/#] &]^8], {n, 1, 50}] (* Vaclav Kotesovec, Feb 07 2019 *)
a[1] = 1; a[n_] := Times @@ (1 + First[#]^(8*Last[#]) & /@ FactorInteger[n]); s = Array[a, 50] (* Amiram Eldar, Aug 10 2019 *)
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
STATUS
approved