OFFSET
0,3
FORMULA
G.f. A(x) = series-reversion of (G(-x)+x)/x where G(x) is g.f. for A030266.
EXAMPLE
Series reversion of g.f.:
x + 2*x^2 + 2*x^3 + 3*x^4 + 13*x^6 - 50*x^7 + 289*x^8 -+...
equals (G(-x)+x)/x where G(x) is g.f. for A030266:
x - 2*x^2 + 6*x^3 - 23*x^4 + 104*x^5 - 531*x^6 +-...
PROG
(PARI) {a(n)=local(A, B, F); if(n<1, 0, F=x+2*x^2-3*x^3+x*O(x^n); A=F; for(j=0, n, for(i=0, j, B=serreverse(A); A=(A+subst(B, x, A/(1-x)))/2); A=round(A)); polcoeff(A/(1-x), n, x))}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, May 12 2005
STATUS
approved