login
A113388
Column 0 of triangle A113387, also equals column 0 of A113389^2.
3
1, 6, 48, 605, 11196, 280440, 8981460, 353283128, 16567072675, 905357065354, 56632746126107, 3997082539456084, 314584709388906568, 27340439653453247728, 2602372304420672868499, 269388182085308601450047
OFFSET
0,2
FORMULA
A113387 equals the matrix cube of A113381, which has the property: column k of A113381^3 = column 0 of A113389^(3*k+2) for k>=0.
PROG
(PARI) a(n)=local(A, B); A=Mat(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^(3*j-2))[i-j+1, 1])); )); A=B); (matrix(#A, #A, r, c, if(r>=c, (A^(3*c-1))[r-c+1, 1]))^3)[n+1, 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 14 2005
STATUS
approved