OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..250
FORMULA
a(n) = n! + 2*floor(e*n!)-2, n>0. - Gary Detlefs, Jun 06 2010
E.g.f.: (1 + 2 * x * exp(x)) / (1 - x). - Ilya Gutkovskiy, Oct 11 2021
MATHEMATICA
FoldList[#1*#2 + 2 #2 &, 1, Range[19]](* Robert G. Wilson v, Jul 07 2012 *)
NestList[{#[[1]]+1, (#[[1]]+1)(#[[2]]+2)}&, {0, 1}, 20][[All, 2]] (* Harvey P. Dale, Jul 03 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Philippe Deléham, Sep 26 2009
EXTENSIONS
Definition corrected by Philippe Deléham, Sep 28 2009
STATUS
approved