OFFSET
0,8
FORMULA
G.f. A(x) satisfies: A(x) = x^2 * (1 + x * A(x)^2) / (1 - x).
MATHEMATICA
a[0] = a[1] = 0; a[2] = 1; a[n_] := a[n] = a[n - 1] + Sum[a[k] a[n - k - 3], {k, 0, n - 3}]; Table[a[n], {n, 0, 44}]
nmax = 44; A[_] = 0; Do[A[x_] = x^2 (1 + x A[x]^2)/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 23 2022
STATUS
approved