A145090 - OEIS

A145090

G.f. satisfies: A(x) = A(y^2)/(1-y) where y = x*A(x).

1, 1, 3, 9, 34, 131, 542, 2297, 10043, 44722, 202669, 930527, 4321859, 20264186, 95802300, 456152409, 2185541010, 10529301243, 50976432986, 247881491762, 1210135732693, 5928928117319, 29142693939368, 143671971795711

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..23.

FORMULA

G.f. satisfies: A(x) = (1-z)*A( z*(1-z)/A(x) ) where z = sqrt(x).

EXAMPLE

A(x) = 1 + x + 3*x^2 + 9*x^3 + 34*x^4 + 131*x^5 + 542*x^6 + 2297*x^7 +...

A(x*(1-x)/A(x^2))*(1-x) = 1 + x^2 + 3*x^4 + 9*x^6 + 34*x^8 + 131*x^10 +...

PROG

(PARI) {a(n)=local(A=1+x); for(n=1, n, A=1/x*serreverse(x/(subst(A, x, x^2+x*O(x^33))/(1-x)))); polcoeff(A, n)}

CROSSREFS

Sequence in context: A149010 A149011 A149012 * A273095 A137953 A353944

Adjacent sequences: A145087 A145088 A145089 * A145091 A145092 A145093

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Oct 21 2008

STATUS

approved