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Column 0 of triangle A113355, which is the matrix square of A113350.
4

%I #5 Jun 13 2017 22:51:27

%S 1,4,18,112,965,10957,156699,2727793,56306695,1350043964,36979531548,

%T 1141573025171,39272377323692,1491452150268435,62027842189908230,

%U 2805631215820328991,137199563717151509076,7215932308408758314446

%N Column 0 of triangle A113355, which is the matrix square of A113350.

%F a(n) = A113346(n+1) - 1, where A113346 equals column 0 of triangle A113345 (=A113340^2).

%o (PARI) a(n)=local(A,B);A=matrix(1,1);A[1,1]=1;for(m=2,n+1,B=matrix(m,m); for(i=1,m, for(j=1,i,if(i<3 || j==i || j>m-1,B[i,j]=1,if(j==1, B[i,1]=1,B[i,j]=(A^(2*j-1))[i-j+1,1]));));A=B); (matrix(#A,#A,r,c,if(r>=c,(A^(2*c))[r-c+1,1]))^2)[n+1,1]

%Y Cf. A113340, A113350, A113355, A113357 (column 1), A113358 (column 2), A113359 (column 3).

%K nonn

%O 0,2

%A _Paul D. Hanna_, Nov 08 2005