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 A293122 #13 Oct 01 2017 00:18:24
%S A293122 1,0,-2,6,-12,0,240,-2520,21840,-181440,1481760,-11642400,80498880,
%T A293122 -311351040,-4739454720,183437654400,-4300276780800,88851284121600,
%U A293122 -1754954007206400,34107089784768000,-659574028252339200,12724865943229440000,-244046146272658329600
%N A293122 E.g.f.: exp(-x^2/(1+x)).
%H A293122 Seiichi Manyama, <a href="/A293122/b293122.txt">Table of n, a(n) for n = 0..450</a>
%F A293122 a(n) = (-1)^n * A293117(n).
%t A293122 CoefficientList[Series[E^(-x^2/(1+x)), {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Sep 30 2017 *)
%o A293122 (PARI) x='x+O('x^66); Vec(serlaplace(exp(-x^2/(1+x))))
%Y A293122 Column k=1 of A293134.
%Y A293122 Cf. A293117.
%K A293122 sign
%O A293122 0,3
%A A293122 _Seiichi Manyama_, Sep 30 2017