A132618 Column 2 of triangle A132615.

1, 1, 5, 56, 1020, 26015, 855478, 34461260, 1642995124, 90456911140, 5646312067585, 393937815588880, 30374808071994000, 2564601377235725520, 235302361169390146650, 23309583579201438877060

Offset

0,3

Comments

Triangle T=A132615 is generated by odd matrix powers of itself such that row n+1 of T = row n of T^(2n-1) with appended '1' for n>=0 with T(0,0)=1.

Links

Table of n, a(n) for n=0..15.

Prog

(PARI) {a(n)=local(A=vector(n+1), p); A[1]=1; for(j=1, n-1, p=(n+1)*n-(n-j+1)*(n-j); A=Vec((Polrev(A)+x*O(x^p))/(1-x))); A=Vec((Polrev(A)+x*O(x^p))/(1-x)); A[p+1]}

Crossrefs

Cf. A132615 (triangle); other columns: A132616, A132617; A132619.

Sequence in context: A217817 A217818 A217819 * A371314 A192562 A060080

Adjacent sequences: A132615 A132616 A132617 * A132619 A132620 A132621

Keyword

nonn

Author

Paul D. Hanna, Aug 24 2007

Status

approved