A166906 Column 1 of triangle A166905.

1, 4, 33, 380, 5510, 95732, 1933288, 44437080, 1144564278, 32638644236, 1020503373032, 34708182795156, 1275532011982176, 50365443858930384, 2126358227959866224, 95577781657788563192, 4556923094838105968302

Offset

0,2

Comments

Triangle A166905 transforms rows into diagonals in the table A158825 of coefficients in successive iterations of x*Catalan(x) (cf. A000108).

Links

Table of n, a(n) for n=0..16.

Prog

(PARI) {a(n)=local(F=x, G=serreverse(x-x^2+O(x^(n+4))), M, N, P, m=n); M=matrix(m+3, m+3, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, G+x*O(x^(m+3)))); polcoeff(F, c)); N=matrix(m+2, m+2, r, c, F=x; for(i=1, r, F=subst(F, x, G+x*O(x^(m+3)))); polcoeff(F, c)); P=matrix(m+2, m+2, r, c, M[r+1, c]); (P~*N~^-1)[n+2, 2]}

Crossrefs

Cf. A166905, A158831, A166907, A166908, A166909.

Sequence in context: A113170 A187738 A198900 * A293020 A293193 A295256

Adjacent sequences: A166903 A166904 A166905 * A166907 A166908 A166909

Keyword

nonn

Author

Paul D. Hanna, Nov 28 2009

Status

approved