OFFSET
1,2
FORMULA
E.g.f. A(x) satisfies: A(x) = x * exp(-Sum_{k>=1} Sum_{d|k} (-A(x^d))^(k/d) / k).
MATHEMATICA
terms = 21; A[_] = 0; Do[A[x_] = x Product[(1 + A[x^k])^(1/k), {k, 1, terms}] + O[x]^(terms + 1) // Normal, terms + 1]; CoefficientList[A[x], x] Range[0, terms]! // Rest
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, May 23 2019
STATUS
approved