This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A386749 #18 Aug 03 2025 10:12:10
%S A386749 0,1,34,246,1092,3130,8364,16814,34952,59787,106420,161062,268632,
%T A386749 371306,571676,769980,1118480,1419874,2032758,2476118,3417960,4136244,
%U A386749 5476108,6436366,8598192,9781275,12624404,14528268,18360888,20511178,26179320,28629182,35791392,39621252
%N A386749 a(n) = n*sigma_4(n).
%H A386749 Vincenzo Librandi, <a href="/A386749/b386749.txt">Table of n, a(n) for n = 0..9000</a>
%F A386749 G.f.: Sum_{k>=1} k^5*x^(k-1)/(1 - x^k)^2.
%F A386749 a(n) = n*A001159(n).
%F A386749 Dirichlet g.f.: zeta(s-1)*zeta(s-5). - _R. J. Mathar_, Aug 03 2025
%t A386749 Table[n*DivisorSigma[4, n], {n, 0, 50}]
%t A386749 nmax = 50; CoefficientList[Series[x*Sum[k^5*x^(k-1)/(1 - x^k)^2, {k, 1, nmax}], {x, 0, nmax}], x]
%o A386749 (Magma) [0] cat [n*DivisorSigma(4, n): n in [1..35]]; // _Vincenzo Librandi_, Aug 02 2025
%o A386749 (PARI) a(n) = if (n, n*sigma(n,4), 0); \\ _Michel Marcus_, Aug 02 2025
%Y A386749 Cf. A064987, A328259, A281372, A282050, A386750, A282060, A386751.
%Y A386749 Cf. A001159, A386747, A386748.
%K A386749 nonn,mult
%O A386749 0,3
%A A386749 _Vaclav Kotesovec_, Aug 01 2025