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 A292358 #14 May 27 2018 19:46:09
%S A292358 1,-1,1,-5,20,-104,584,-4304,35720,-329160,3239112,-36135912,
%T A292358 438454752,-5743527360,80351263680,-1218698312064,19599583392384,
%U A292358 -334335747652224,6019295318075520,-114911886106373760,2305234779285164544,-48596575400453366784
%N A292358 E.g.f.: Product_{k>=1} 1/(1 + x^k/k).
%H A292358 Seiichi Manyama, <a href="/A292358/b292358.txt">Table of n, a(n) for n = 0..449</a>
%F A292358 a(n) ~ (-1)^n * n!. - _Vaclav Kotesovec_, Sep 15 2017
%F A292358 E.g.f.: exp(Sum_{k>=1} Sum_{j>=1} (-1)^k*x^(j*k)/(k*j^k)). - _Ilya Gutkovskiy_, May 27 2018
%t A292358 nmax = 20; CoefficientList[Series[Product[1/(1 + x^k/k), {k, 1, nmax}], {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Sep 15 2017 *)
%o A292358 (PARI) {a(n) = n!*polcoeff(1/prod(k=1, n, 1+x^k/k+x*O(x^n)), n)}
%Y A292358 Cf. A007838, A007841.
%K A292358 sign
%O A292358 0,4
%A A292358 _Seiichi Manyama_, Sep 14 2017