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 A307504 #16 Apr 12 2019 09:00:33
%S A307504 1,-1,4,-31,293,-3499,51284,-891276,17928335,-409921846,10500040633,
%T A307504 -297796771914,9262574642871,-313459274848233,11464944476563718,
%U A307504 -450647901022275715,18943108018829605740,-847933752191806388254,40266301788890216414608,-2021846883773977115156632
%N A307504 Expansion of Product_{k>=1} 1/(1-x^k)^((-1)^k*k^k).
%C A307504 This sequence is obtained from the generalized Euler transform in A266964 by taking f(n) = (-1)^n * n^n, g(n) = 1.
%H A307504 Seiichi Manyama, <a href="/A307504/b307504.txt">Table of n, a(n) for n = 0..386</a>
%F A307504 a(n) ~ (-1)^n * n^n * (1 + exp(-1)/n + (exp(-1)/2 + 4*exp(-2))/n^2). - _Vaclav Kotesovec_, Apr 12 2019
%t A307504 nmax=20; CoefficientList[Series[Product[1/(1-x^k)^((-1)^k*k^k), {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 12 2019 *)
%o A307504 (PARI) N=20; x='x+O('x^N); Vec(1/prod(k=1, N, (1-x^k)^((-1)^k*k^k)))
%Y A307504 Cf. A023880, A266964, A307497.
%K A307504 sign
%O A307504 0,3
%A A307504 _Seiichi Manyama_, Apr 11 2019