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 A321389 #11 Apr 02 2019 05:51:24
%S A321389 1,2,10,72,670,7896,113532,1938948,38463150,869969602,22098936536,
%T A321389 622728174288,19271479902324,649553475002720,23680210649058960,
%U A321389 928276725059295192,38931910620358040382,1739307894106738293052,82457731356894087128054,4134332188240252347401752,218571692793801915329820184
%N A321389 Expansion of Product_{k>=1} ((1 + x^k)/(1 - x^k))^(k^k).
%C A321389 Convolution of A023880 and A261053.
%H A321389 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%F A321389 G.f.: exp(Sum_{k>=1} ( Sum_{d|k} ((-1)^(k/d+1) + 1)*d^(d+1) ) * x^k/k).
%F A321389 a(n) ~ 2 * n^n * (1 + 2*exp(-1)/n + (exp(-1) + 10*exp(-2))/n^2). - _Vaclav Kotesovec_, Nov 09 2018
%p A321389 a:=series(mul(((1+x^k)/(1-x^k))^(k^k),k=1..100),x=0,21): seq(coeff(a,x,n),n=0..20); # _Paolo P. Lava_, Apr 02 2019
%t A321389 nmax = 20; CoefficientList[Series[Product[((1 + x^k)/(1 - x^k))^(k^k), {k, 1, nmax}], {x, 0, nmax}], x]
%t A321389 a[n_] := a[n] = If[n == 0, 1, Sum[Sum[((-1)^(k/d + 1) + 1) d^(d + 1), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 20}]
%o A321389 (PARI) seq(n)={Vec(exp(sum(k=1, n, sumdiv(k,d, ((-1)^(k/d+1) + 1)*d^(d+1) ) * x^k/k) + O(x*x^n)))} \\ _Andrew Howroyd_, Nov 09 2018
%Y A321389 Cf. A023880, A156616, A206622, A206623, A206624, A261053.
%K A321389 nonn
%O A321389 0,2
%A A321389 _Ilya Gutkovskiy_, Nov 08 2018