A176201 G.f. satisfies A(x)/A(x^2) = (1 + 9x + 9x^2 + 9x^3 + ...).

1, 9, 18, 90, 108, 252, 342, 1062, 1170, 2034, 2286, 4302, 4644, 7380, 8442, 16938, 18108, 27468, 29502, 45774, 48060, 66348, 70650, 105066, 109710, 146862, 154242, 213282, 221724, 289260, 306198, 441702, 459810, 604674, 632142

Offset

0,2

Links

Table of n, a(n) for n=0..34.

Formula

Let M = an infinite lower triangular matrix with (1, 9, 9, 9,...) in each column but stepped down twice from the previous column for (k>0). Then A176201 = Lim_{n->inf.} M^n, the left-shifted vector considered as a sequence.

Prog

(PARI) lista(n)= {local(A=1+9*x); for (i=1, n, A = subst(A, x, x^2)*(9*(1-x^i)/(1-x) - 8); A = subst(A, x, x+O(x^i)); print1(polcoeff(A, i-1), ", "); ); } \\ Michel Marcus, Jul 15 2013

Crossrefs

Sequence in context: A140149 A197345 A186951 * A186443 A066711 A033651

Adjacent sequences: A176198 A176199 A176200 * A176202 A176203 A176204

Keyword

nonn

Author

Gary W. Adamson, Apr 11 2010

Extensions

Corrected and more terms from Michel Marcus, Jul 19 2013

Status

approved