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 A293590 #7 Oct 13 2017 05:28:47 %S A293590 1,0,0,6,-24,0,360,0,-20160,60480,1814400,-19958400,-59875200, %T A293590 2075673600,21794572800,-860885625600,3487131648000,148203095040000, %U A293590 -524638956441600,-71973351075225600,942749528168448000,19878836825143296000,-437111394135736320000 %N A293590 E.g.f.: exp(x^3/(1 + x + x^2 + x^3)). %F A293590 E.g.f.: Product_{k>0} exp(x^(4*k-1)) / exp(x^(4*k)). %t A293590 CoefficientList[Series[E^(x^3/(1 + x + x^2 + x^3)), {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Oct 13 2017 *) %o A293590 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x^3/(1+x+x^2+x^3)))) %o A293590 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(prod(k=1, N, exp(x^(4*k-1)-x^(4*k))))) %Y A293590 Cf. A111884, A293589. %K A293590 sign %O A293590 0,4 %A A293590 _Seiichi Manyama_, Oct 12 2017