OFFSET
0,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..500
FORMULA
a(0) = 1 and a(n) = - (n-1)! * Sum_{k=1..min(3,n)} k*a(n-k)/(n-k)!.
D-finite with recurrence a(n) + a(n-1) +2*(n-1)*a(n-2) +3*(n-1)*(n-2)*a(n-3)=0. - R. J. Mathar, May 07 2020
MATHEMATICA
With[{nn=30}, CoefficientList[Series[Exp[-(x+x^2+x^3)], {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, Nov 26 2020 *)
PROG
(PARI) N=40; x='x+O('x^N); Vec(serlaplace(exp(-x-x^2-x^3)))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, May 06 2020
STATUS
approved