OFFSET
0,2
LINKS
Robert Israel, Table of n, a(n) for n = 0..317
FORMULA
MAPLE
A[0]:= x -> 1+c*x:
for n from 1 to 20 do
cc:= coeff(series(A[n-1](x/A[n-1](x))-1/(1-x)^6, x, n+1), x, n);
A[n]:= unapply(eval(A[n-1](x), c=solve(cc, c))+c*x^(n+1), x);
od:
seq(coeff(A[20](x), x, j), j=0..20); # Robert Israel, Aug 19 2018
MATHEMATICA
nmax = 16; sol = {a[0] -> 1};
Do[A[x_] = Sum[a[k] x^k, {k, 0, n}] /. sol; eq = CoefficientList[A[x/A[x]] - 1/(1 - x)^6 + O[x]^(n + 1), x] == 0 /. sol; sol = sol ~Join~ Solve[eq] [[1]], {n, 1, nmax}]; sol /. Rule -> Set;
a /@ Range[0, nmax] (* Jean-François Alcover, Nov 01 2019 *)
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n), B); for(n=0, n, B=serreverse(x/A); A=1/(1-B)^6); polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 03 2008
STATUS
approved