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 A136226 #3 Mar 30 2012 18:37:08
%S A136226 1,2,8,49,414,4529,61369,996815,18931547,412345688,10143253814,
%T A136226 278322514093,8432315243347,279689506725247,10083429764179733,
%U A136226 392703359698462567,16433405366965493214,735484032071079495354
%N A136226 Column 0 of P^2 where triangle P = A136220; also equals column 1 of square array A136217.
%F A136226 Equals column 0 of triangle V = A136230, where column k of V = column 0 of P^(3k+2) such that column k of P^2 = column 0 of V^(k+1), for k>=0 and where P = A136220.
%o A136226 (PARI) /* Generate using matrix product recurrences of triangle P=A136220: */ {a(n)=local(P=Mat(1),U,PShR);if(n>0,for(i=0,n, PShR=matrix(#P,#P, r,c, if(r>=c,if(r==c,1,if(c==1,0,P[r-1,c-1]))));U=P*PShR^2; U=matrix(#P+1, #P+1, r,c, if(r>=c, if(r<#P+1,U[r,c], if(c==1,(P^3)[ #P,1],(P^(3*c-1))[r-c+1,1])))); P=matrix(#U, #U, r,c, if(r>=c, if(r<#R,P[r,c], (U^c)[r-c+1,1])))));(P^2)[n+1,1]}
%Y A136226 Cf. A136225 (P^2), A136220 (P), A136230 (V); A136217.
%K A136226 nonn
%O A136226 0,2
%A A136226 _Paul D. Hanna_, Jan 28 2008