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 A000222 M2602 N1029 #33 Jun 13 2019 19:56:11
%S A000222 0,0,1,3,6,38,213,1479,11692,104364,1036809,11344859,135548466,
%T A000222 1755739218,24504637741,366596136399,5852040379224,99283915922264,
%U A000222 1783921946910417,33840669046326579,675849838112277598,14174636583759324798
%N A000222 Coefficients of ménage hit polynomials.
%D A000222 J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 198.
%D A000222 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A000222 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A000222 Alois P. Heinz, <a href="/A000222/b000222.txt">Table of n, a(n) for n = 0..150</a>
%H A000222 R. C. Read, <a href="/A000684/a000684_1.pdf">Letter to N. J. A. Sloane, Oct. 29, 1976</a>
%F A000222 a(n) ~ 2/exp(2) * n!. - _Vaclav Kotesovec_, Sep 06 2014
%F A000222 a(n)+2*a(n+p)+a(n+2*p) is divisible by p for any prime p. - _Mark van Hoeij_, Jun 13 2019
%t A000222 max = 30; f[x_, y_] := Sum[n!*((x*y)^n/(1+x*(y-1))^(2*n+1)), {n, 0, max}]; t = MapIndexed[Take[#1, First[#2]]&, CoefficientList[Series[f[x, y], {x, 0, max}, {y, 0, max}], {x, y}]] ; a[0] = a[1] = 0; a[n_] := t[[n+1, n-1]]; Table[a[n], {n, 0, max}] (* _Jean-François Alcover_, Mar 11 2014, after _Vladeta Jovovic_ *)
%Y A000222 A diagonal of A058057.
%K A000222 nonn
%O A000222 0,4
%A A000222 _N. J. A. Sloane_, _Simon Plouffe_