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 A363639 #14 Jul 17 2023 00:59:30
%S A363639 3,12,19,51,36,180,57,405,352,918,111,3990,144,5064,6534,15945,222,
%T A363639 51462,267,99354,82478,160812,369,808490,66051,861630,1090342,2593614,
%U A363639 552,8966414,621,13039761,13831470,22415778,3166218,114011229,852,110103540,167426822
%N A363639 Expansion of Sum_{k>0} (1/(1 - k*x^k)^3 - 1).
%F A363639 a(n) = Sum_{d|n} (n/d)^d * binomial(d+2,2).
%t A363639 a[n_] := DivisorSum[n, (n/#)^# * Binomial[# + 2, 2] &]; Array[a, 40] (* _Amiram Eldar_, Jul 17 2023 *)
%o A363639 (PARI) a(n) = sumdiv(n, d, (n/d)^d*binomial(d+2, 2));
%Y A363639 Cf. A338662, A362683, A363640.
%Y A363639 Cf. A363642, A363643, A363644.
%Y A363639 Cf. A363628, A363647.
%K A363639 nonn
%O A363639 1,1
%A A363639 _Seiichi Manyama_, Jun 13 2023