OFFSET
0,3
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..400
FORMULA
G.f. A(x) satisfies: A(x) = Sum_{k>=0} A000670(k)*x^k*A(x)^k.
G.f.: A(x) = (1/x)*Series_Reversion(x/Sum_{k>=0} A000670(k)*x^k).
a(n) ~ n! / (log(2))^(n+1). - Vaclav Kotesovec, Apr 07 2019
EXAMPLE
G.f.: A(x) = 1 + x + 4*x^2 + 23*x^3 + 164*x^4 + 1362*x^5 + 12792*x^6 + 133891*x^7 + 1550148*x^8 + 19772030*x^9 + 277054232*x^10 + ...
MATHEMATICA
terms = 22; A[_] = 1; Do[A[x_] = Sum[j! x^j A[x]^j/Product[(1 - k x A[x]), {k, 1, j}], {j, 0, i}] + O[x]^i, {i, 1, terms}]; CoefficientList[A[x], x]
terms = 22; A[_] = 1; Do[A[x_] = Sum[(1/2) HurwitzLerchPhi[1/2, -k, 0] x^k A[x]^k, {k, 0, j}] + O[x]^j, {j, 1, terms}]; CoefficientList[A[x], x]
terms = 22; CoefficientList[1/x InverseSeries[Series[x/Sum[(1/2) HurwitzLerchPhi[1/2, -k, 0] x^k, {k, 0, terms}], {x, 0, terms}], x], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 07 2019
STATUS
approved