OFFSET
0,3
FORMULA
a(n) ~ 2^(4*n + 7/2) * n^(3*n + 1) / (exp(3*n) * Pi^(2*n)).
MATHEMATICA
nmax = 20; CoefficientList[Series[1/(1 + ContinuedFractionK[-k^2*x*Exp[x], 1, {k, 1, nmax}]), {x, 0, nmax}], x] * Range[0, nmax]!
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Sep 14 2021
STATUS
approved