A136233 Matrix square of triangle U = A136228, read by rows.
1, 2, 1, 10, 8, 1, 75, 76, 14, 1, 753, 888, 196, 20, 1, 9534, 12542, 3087, 370, 26, 1, 146353, 209506, 55552, 7320, 598, 32, 1, 2647628, 4058806, 1136975, 159645, 14235, 880, 38, 1, 55251994, 89706276, 26224597, 3856065, 364403, 24480, 1216, 44, 1
Offset: 0
Examples
This triangle, U^2, begins: 1; 2, 1; 10, 8, 1; 75, 76, 14, 1; 753, 888, 196, 20, 1; 9534, 12542, 3087, 370, 26, 1; 146353, 209506, 55552, 7320, 598, 32, 1; 2647628, 4058806, 1136975, 159645, 14235, 880, 38, 1; 55251994, 89706276, 26224597, 3856065, 364403, 24480, 1216, 44, 1; ... where column 0 of U^2 = column 1 of P = A136220.
Crossrefs
Programs
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PARI
{T(n,k)=local(P=Mat(1),U=Mat(1),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])))));(U^2)[n+1,k+1]}
Formula
Column k of U^2 (this triangle) = column 1 of P^(3k+1), where P = triangle A136220.