OFFSET
1,3
FORMULA
a(n) = (3/2)*(-1)^n*A139087(n) for n>2 with a(1)=a(2)=1.
EXAMPLE
G.f.: A(x) = x + x^2 + 6*x^3 + 75*x^4 + 1338*x^5 + 29610*x^6 +...
Series_Reversion(A(x)) = x - x^2 - 4*x^3 - 50*x^4 - 892*x^5 - ...
which equals -G(-x) where G(x) = g.f. of A139087.
PROG
(PARI) {a(n)=local(A=x+x^2); if(n<1, 0, for(i=3, n+1, A=A+3*polcoeff(serreverse(A+x*O(x^i)), i)*x^i); polcoeff(A, n))}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Apr 08 2008
STATUS
approved