OFFSET
0,3
FORMULA
a(n) = (n!)^2 * [x^n] exp(sqrt(x) * BesselI(1,2*sqrt(x))).
MATHEMATICA
a[0] = 1; a[n_] := a[n] = n Sum[Binomial[n - 1, k]^2 a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 18}]
nmax = 18; CoefficientList[Series[Exp[Sqrt[x] BesselI[1, 2 Sqrt[x]]], {x, 0, nmax}], x] Range[0, nmax]!^2
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jul 12 2020
STATUS
approved