OFFSET
1,3
COMMENTS
Apart from signs, essentially the same as A138740.
Apparently a(n) = A276370(n) wherever defined. - R. J. Mathar, Sep 26 2017
LINKS
Paul D. Hanna, Table of n, a(n) for n = 1..300
EXAMPLE
G.f.: A(x) = x + x^2 + 2*x^3 + 9*x^4 + 56*x^5 + 420*x^6 + 3572*x^7 + 33328*x^8 + 334354*x^9 + 3559310*x^10 + 39838760*x^11 + 465743720*x^12 + 5658983108*x^13 + 71191948512*x^14 + 924554859776*x^15 + 12365546196641*x^16 +...
such that A( 2*x - A(x) ) = 2*x - A(x) + x^2.
PROG
(PARI) {a(n) = my(A=x, V=[1, 1]); for(i=1, n, V = concat(V, 0); A=x*Ser(V); V[#V] = Vec( subst(G=A, x, 2*x - A) )[#V]/(-1) ); V[n]}
for(n=1, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 24 2017
STATUS
approved