OFFSET
0,3
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..160
FORMULA
G.f. satisfies: 1 - 1/A(x) = x*A( 1 - 1/A(x) )^2.
Self-convolution yields A145159.
EXAMPLE
G.f.: A(x) = 1 + x + 3*x^2 + 16*x^3 + 121*x^4 + 1143*x^5 +...
x/A(x)^2 = x - 2*x^2 - 3*x^3 - 18*x^4 - 150*x^5 - 1518*x^6 -...
1/A(x) = 1 - x - 2*x^2 - 11*x^3 - 88*x^4 - 869*x^5 - 9876*x^6 -...
Series_Reversion[x/A(x)^2] = x + 2*x^2 + 11*x^3 + 88*x^4 + 869*x^5 +...
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(n=0, n, B=serreverse(x/A^2); A=1/(1-B)); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 03 2008
STATUS
approved