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 A054092 #8 May 21 2014 19:37:48
%S A054092 1,1,1,3,7,25,105,547,3367,24033,195169,1777651,17950551,199059673,
%T A054092 2405063017,31448531955,442501797655,6666753146497,107081325959937,
%U A054092 1826636018849443,32980276187719399,628351055737088601
%N A054092 T(n,n), array T as in A054090.
%o A054092 (PARI) {a(n)= local(A); if(n<3, n>=0, A=vector(n, i, 1); for(k=1, n-2, A[k+2]=(k-1)*A[k+1]+ k*A[k]+ 2); A[n])} /* _Michael Somos_, Nov 19 2006 */
%K A054092 nonn
%O A054092 0,4
%A A054092 _Clark Kimberling_