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 A293072 #19 Oct 05 2017 11:35:17
%S A293072 1,-1,1,0,0,-3,4,-3,4,-2,0,-6,9,-10,10,-5,10,-16,20,-28,22,-18,19,-32,
%T A293072 54,-50,45,-38,44,-78,106,-118,96,-98,110,-129,192,-216,204,-182,213,
%U A293072 -286,368,-412,366,-362,394,-524,676,-714,680,-641,742,-936,1170
%N A293072 G.f.: Product_{m>0} (1-x^m+2!*x^(2*m)).
%H A293072 Alois P. Heinz, <a href="/A293072/b293072.txt">Table of n, a(n) for n = 0..10000</a> (first 501 terms from Seiichi Manyama)
%p A293072 b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
%p A293072 add(b(n-i*j, i-1)*j!*(-1)^j, j=0..min(2, n/i))))
%p A293072 end:
%p A293072 a:= n-> b(n$2):
%p A293072 seq(a(n), n=0..60); # _Alois P. Heinz_, Oct 04 2017
%t A293072 nmax = 100; CoefficientList[Series[Product[1 - x^k + 2*x^(2*k), {k, 1, nmax}], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Oct 05 2017 *)
%o A293072 (PARI) Vec(prod(m=1, 80, 1-x^m+2*x^(2*m)) + O(x^80)) \\ _Michel Marcus_, Oct 04 2017
%Y A293072 Column k=2 of A293071.
%Y A293072 Cf. A293204, A293304.
%K A293072 sign
%O A293072 0,6
%A A293072 _Seiichi Manyama_, Oct 03 2017