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 A293572 #10 May 05 2020 19:27:40
%S A293572 1,1,-1,-5,1,161,31,-8021,-14335,686881,2925631,-91860229,-583959551,
%T A293572 15741408385,169511794271,-3832934048789,-54596554106879,
%U A293572 1106568438159809,23024933751472255,-412744343093399429,-11208399032299519999,177909311974519181281
%N A293572 E.g.f.: exp(x/(1 + x + x^2 + x^3)).
%H A293572 Robert Israel, <a href="/A293572/b293572.txt">Table of n, a(n) for n = 0..446</a>
%F A293572 E.g.f.: Product_{k>0} exp(x^(4*k-3)) / exp(x^(4*k-2)).
%F A293572 n*(n+5)*(n+4)*(n+3)*(n+2)*(n+1)*a(n) + 2*(n+1)*(n+2)*(n+3)*(n+4)*(n+5)*a(n+1) + (n+5)*(n+4)*(n+3)*(8+3*n)*a(n+2) + (n+5)*(n+4)*(13+4*n)*a(n+3) + 3*(n+4)*(n+5)*a(n+4) + (9+2*n)*a(n+5) + a(n+6) = 0. - _Robert Israel_, May 05 2020
%p A293572 f:= gfun:-rectoproc(n*(n+5)*(n+4)*(n+3)*(n+2)*(n+1)*a(n) + 2*(n+1)*(n+2)*(n+3)*(n+4)*(n+5)*a(n+1) + (n+5)*(n+4)*(n+3)*(8+3*n)*a(n+2) + (n+5)*(n+4)*(13+4*n)*a(n+3) + 3*(n+4)*(n+5)*a(n+4) + (9+2*n)*a(n+5) + a(n+6),
%p A293572 a(0) = 1, a(1) = 1, a(2) = -1, a(3) = -5, a(4) = 1, a(5) = 161}, a(n), remember):
%p A293572 map(f, [$0..25]); # _Robert Israel_, May 05 2020
%o A293572 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x/(1+x+x^2+x^3))))
%o A293572 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(prod(k=1, N, exp(x^(4*k-3)-x^(4*k-2)))))
%Y A293572 Cf. A111884, A293571, A293573.
%K A293572 sign
%O A293572 0,4
%A A293572 _Seiichi Manyama_, Oct 12 2017