A113090 Triangle T, read by rows, equal to the matrix cube of triangle A113084, which satisfies the recurrence: A113084(n,k) = [A113084^3](n-1,k-1) + [A113084^3](n-1,k).
1, 3, 1, 21, 12, 1, 331, 255, 39, 1, 11973, 11326, 2442, 120, 1, 1030091, 1136709, 310864, 22206, 363, 1, 218626341, 272246616, 89081163, 8266954, 199839, 1092, 1, 118038692523, 162043308555, 61099562421, 6923071251, 220482175, 1796349
Offset: 0
Examples
Triangle begins: 1; 3,1; 21,12,1; 331,255,39,1; 11973,11326,2442,120,1; 1030091,1136709,310864,22206,363,1; 218626341,272246616,89081163,8266954,199839,1092,1; ...
Programs
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PARI
{T(n,k)=local(M=matrix(n+1,n+1));for(r=1,n+1, for(c=1,r, M[r,c]=if(r==c,1,if(c>1,(M^3)[r-1,c-1])+(M^3)[r-1,c]))); return((M^3)[n+1,k+1])}