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%I #15 May 14 2024 05:12:07
%S 1,10,29,81,121,302,321,630,801,1264,1177,2521,1961,3234,4013,5140,
%T 4267,8013,5921,10701,10685,12166,10321,20458,15552,19610,21469,28473,
%U 20671,40340,25377,40351,39557,43048,45849,70020,43131,59690,63813,89154,58087,106310
%N a(n) = Sum_{k=1..n} sigma(n*k),
%H Vaclav Kotesovec, <a href="/A372710/a372710.jpg">Graph - the asymptotic ratio (100000 terms)</a>
%F Conjecture: a(n) ~ A372675(n) / 2 ~ Pi^4 * n^4 / (288*zeta(3)). - _Vaclav Kotesovec_, May 13 2024
%t Table[Sum[DivisorSigma[1, k*n], {k, 1, n}], {n, 1, 50}] (* _Vaclav Kotesovec_, May 13 2024 *)
%o (PARI) a(n) = sum(k=1, n, sigma(n*k));
%Y Cf. A000203, A024916, A065764, A326124, A372675, A372709.
%K nonn
%O 1,2
%A _Seiichi Manyama_, May 11 2024