OFFSET
0,3
LINKS
Gheorghe Coserea, Table of n, a(n) for n = 0..200
T. R. S. Walsh, A. B. Lehman, Counting rooted maps by genus. III: Nonseparable maps, J. Combinatorial Theory Ser. B 18 (1975), 222-259.
FORMULA
MAPLE
g := 1+x ;
for itr from 2 to 14 do
g := g+a*x^itr;
Ax := add(A035319(i)*x^i, i=0..itr+1) ;
x*Ax^4 ;
z := subs(x=%, g)-Ax ;
z := expand(z) ;
z := taylor(z, x=0, itr+1) ;
z := convert(z, polynom) ;
aa := solve(z, a) ;
g := g-a*x^itr+aa*x^itr ;
print(g) ;
end do:
PROG
(PARI)
seq(N) = {
my(s = 1+'x*Ser(vector(N, n, (4*n)!/((2*n+1)!*4^n))));
Vec(subst(s, 'x, serreverse('x*s^4)));
};
seq(14) \\ Gheorghe Coserea, Jun 13 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Jun 12 2018
STATUS
approved