OFFSET
0,2
FORMULA
MATHEMATICA
nmax = 23; CoefficientList[Series[Exp[2 (x + x^2/2 + x^3/3)], {x, 0, nmax}], x] Range[0, nmax]!
a[0] = 1; a[1] = 2; a[2] = 6; a[n_] := a[n] = 2 (a[n - 1] + (n - 1) a[n - 2] + (n - 1) (n - 2) a[n - 3]); Table[a[n], {n, 0, 23}]
PROG
(PARI) my(x='x+O('x^30)); Vec(serlaplace(exp(2*(x + x^2/2 + x^3/3)))) \\ Michel Marcus, Nov 21 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Nov 20 2020
STATUS
approved