OFFSET
1,4
COMMENTS
Also asymmetric involution rooted trees.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..500
N. J. A. Sloane, Transforms
FORMULA
Shifts left under transform T where Ta = WEIGH(W_1, 2(a)). W_1, 2(a) has g.f. A(x)+(A(x^2)-A(x)^2)/2.
PROG
(PARI) WeighT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, (-1)^(n-1)/n))))-1, -#v)}
seq(n)={my(p=O(x)); for(n=1, n, p=x+x^2*(Ser(WeighT(Vec(p + (p^2 - subst(p, x, x^2))/2))))); Vec(p)} \\ Andrew Howroyd, Aug 30 2018
CROSSREFS
KEYWORD
nonn,eigen
AUTHOR
Christian G. Bower, Jan 14 2004
STATUS
approved