|
%I #19 Oct 11 2021 09:41:24
%S 1,3,10,36,152,770,4632,32438,259520,2335698,23357000,256927022,
%T 3083124288,40080615770,561128620808,8416929312150,134670868994432,
%U 2289404772905378,41209285912296840,782976432333639998,15659528646672800000,328850101580128800042
%N a(0)=1, a(n) = n*(a(n-1)+2).
%H G. C. Greubel, <a href="/A165792/b165792.txt">Table of n, a(n) for n = 0..250</a>
%F a(n) = n! + 2*floor(e*n!)-2, n>0. - _Gary Detlefs_, Jun 06 2010
%F E.g.f.: (1 + 2 * x * exp(x)) / (1 - x). - _Ilya Gutkovskiy_, Oct 11 2021
%t FoldList[#1*#2 + 2 #2 &, 1, Range[19]](* _Robert G. Wilson v_, Jul 07 2012 *)
%t NestList[{#[[1]]+1,(#[[1]]+1)(#[[2]]+2)}&,{0,1},20][[All,2]] (* _Harvey P. Dale_, Jul 03 2021 *)
%Y Cf. A000142, A033540.
%K nonn
%O 0,2
%A _Philippe Deléham_, Sep 26 2009
%E Definition corrected by _Philippe Deléham_, Sep 28 2009
|
