A135889 Column 0 of triangle A135888, which equals the matrix cube of triangle A135880; also equals column 1 of triangle A135894.

1, 3, 12, 63, 421, 3472, 34380, 399463, 5344770, 81097517, 1377986373, 25947738574, 536726987593, 12104879913657, 295754724799758, 7784814503249896, 219682110287448760, 6617691928179590112

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Prog

(PARI) {a(n)=local(P=Mat(1), R, PShR); if(n==0, 1, 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])))); R=P*PShR; R=matrix(#P+1, #P+1, r, c, if(r>=c, if(r<#P+1, R[r, c], if(c==1, (P^2)[ #P, 1], (P^(2*c-1))[r-c+1, 1])))); P=matrix(#R, #R, r, c, if(r>=c, if(r<#R, P[r, c], (R^c)[r-c+1, 1])))); (P^3)[n+1, 1])}

Crossrefs

Cf. A135888, A135890; A135880, A135894.

Sequence in context: A355164 A238887 A351778 * A369746 A124562 A172450

Adjacent sequences: A135886 A135887 A135888 * A135890 A135891 A135892

Keyword

nonn

Author

Paul D. Hanna, Dec 15 2007

Status

approved