A166903 Column 3 of triangle A166900.

1, 16, 230, 3564, 61845, 1207696, 26415840, 642448632, 17240108314, 506777596248, 16210958231104, 560988459704192, 20891752852722701, 833382707754108896, 35461362393617267808, 1603581518693484768464

Offset

0,2

Comments

Triangle A166900 transforms rows into diagonals in the table of coefficients of successive iterations of x+x^2 (cf. A122888).

Links

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

Prog

(PARI) {a(n)=local(F=x, M, N, P); M=matrix(n+5, n+5, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, x+x^2+x*O(x^(n+5)))); polcoeff(F, c)); N=matrix(n+4, n+4, r, c, F=x; for(i=1, r, F=subst(F, x, x+x^2+x*O(x^(n+5)))); polcoeff(F, c)); P=matrix(n+4, n+4, r, c, M[r+1, c]); (P~*N~^-1)[n+4, 4]}

Crossrefs

Cf. A166900, A166901, A166902, A166904, A122888, A135080.

Sequence in context: A014897 A048445 A028340 * A230234 A274467 A119463

Adjacent sequences: A166900 A166901 A166902 * A166904 A166905 A166906

Keyword

nonn

Author

Paul D. Hanna, Nov 27 2009

Status

approved