%I #5 Jun 13 2017 23:38:46
%S 1,3,9,27,89,327,1353,6303,32953,192395,1247473,8931643,70221841,
%T 603040399,5628477521,56832554399,618172840753,7214736795987,
%U 90023735419577,1196943617218715,16905957430843689,252946811300548119
%N Column 2 of triangle A113993, also equals column 0 of A113983^3.
%e A113983^3, the matrix cube of triangle A113983, begins:
%e 1;
%e 3,1;
%e 9,6,1;
%e 27,27,9,1;
%e 89,117,57,12,1;
%e 327,529,333,99,15,1;
%e 1353,2583,1965,735,153,18,1;
%e 6303,13815,12185,5393,1383,219,21,1;
%e 32953,81321,80865,40785,12169,2337,297,24,1; ...
%o (PARI) a(n)=local(A,B);A=Mat(1);for(m=2,n+2,B=matrix(m,m); for(i=1,m, for(j=1,i,if(i<3 || j==1 || j==i,B[i,j]=1, B[i,j]=A[i-1,j-1]+(A^2)[i-2,j-1] );));A=B);(A^3)[n+1,1]
%Y Cf. A113993, A113989 (column 1), A113995 (column 3), A113996 (column 4), A113997 (row sums); A113983.
%K nonn
%O 0,2
%A _Paul D. Hanna_, Nov 12 2005
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