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%I #13 Dec 15 2023 06:19:25
%S 0,1,1,3,1,19,1,7,4,37,1,67,1,63,43,15,1,145,1,121,69,139,1,211,6,189,
%T 13,199,1,661,1,31,145,313,87,475,1,387,195,337,1,1155,1,427,241,559,
%U 1,691,8,817,319,577,1,1171,163,519,393,877,1,2413,1,999,345,63,213,2599
%N a(n) = sigma(n^2) - n*sigma(n).
%H Michel Marcus, <a href="/A086156/b086156.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A065764(n) - A064987(n). - _Michel Marcus_, Aug 23 2019
%F Sum_{k=1..n} a(k) ~ (5*zeta(3)/Pi^2 - Pi^2/18) * n^3. - _Amiram Eldar_, Dec 15 2023
%t Table[DivisorSigma[1, w*w]-w*DivisorSigma[1, w], {w, 1, 256}]
%o (PARI) a(n) = sigma(n^2) - n*sigma(n); \\ _Michel Marcus_, Aug 23 2019
%Y Cf. A000203, A000593, A046913, A064987, A065764.
%K nonn,easy
%O 1,4
%A _Labos Elemer_, Aug 14 2003