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 A291489 #5 Feb 16 2025 08:33:50
%S A291489 1,-2,3,2,-41,196,-541,229,7235,-48228,175956,-254933,-1575661,
%T A291489 14909191,-67194669,153944915,292516673,-4968647665,27275432639,
%U A291489 -82747735226,3883854725,1660136515050,-11302429310683,42362000190568,-53376259124482,-520085199830413,4671353423344131
%N A291489 Expansion of the series reversion of -1 + Product_{k>=1} (1 + x^k)^k.
%C A291489 Reversion of g.f. (with constant term omitted) for A026007.
%H A291489 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%H A291489 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SeriesReversion.html">Series Reversion</a>
%H A291489 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A291489 G.f. A(x) satisfies: -1 + Product_{k>=1} (1 + A(x)^k)^k = x.
%t A291489 nmax = 27; Rest[CoefficientList[InverseSeries[Series[-1 + Product[(1 + x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x], x]]
%t A291489 nmax = 27; Rest[CoefficientList[InverseSeries[Series[-1 + Exp[Sum[(-1)^(k + 1) x^k/(k (1 - x^k)^2), {k, 1, nmax}]], {x, 0, nmax}], x], x]]
%Y A291489 Cf. A007312, A026007, A050393, A176025.
%K A291489 sign
%O A291489 1,2
%A A291489 _Ilya Gutkovskiy_, Aug 24 2017