%I #27 Nov 14 2022 01:40:03
%S 1,256,6561,65792,390625,1679616,5764801,16842752,43053282,100000000,
%T 214358881,431661312,815730721,1475789056,2562890625,4311810048,
%U 6975757441,11021640192,16983563041,25700000000,37822859361,54875873536,78310985281,110505295872,152588281250
%N a(n) = n^8 * Sum_{d^2|n} 1 / d^8.
%H Seiichi Manyama, <a href="/A351606/b351606.txt">Table of n, a(n) for n = 1..10000</a>
%F Multiplicative with a(p^e) = p^8*(p^(8*e) - p^(8*floor((e-1)/2)))/(p^8 - 1). - _Sebastian Karlsson_, Feb 25 2022
%F Sum_{k=1..n} a(k) ~ c * n^9, where c = zeta(10)/9 = Pi^10/841995 = 0.1112216... . - _Amiram Eldar_, Nov 13 2022
%t f[p_, e_] := p^8*(p^(8*e) - p^(8*Floor[(e - 1)/2]))/(p^8 - 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 30] (* _Amiram Eldar_, Nov 13 2022 *)
%o (PARI) a(n) = n^8*sumdiv(n, d, if (issquare(d), 1/d^4)); \\ _Michel Marcus_, Feb 15 2022
%Y Sequences of the form n^k * Sum_{d^2|n} 1/d^k for k = 0..10: A046951 (k=0), A340774 (k=1), A351600 (k=2), A351601 (k=3), A351602 (k=4), A351603 (k=5), A351604 (k=6), A351605 (k=7), this sequence (k=8), A351607 (k=9), A351608 (k=10).
%Y Cf. A013668.
%K nonn,mult
%O 1,2
%A _Wesley Ivan Hurt_, Feb 14 2022