A082570 - OEIS

%I #7 Mar 30 2012 18:39:17

%S 1,4,13,53,266,1597,11180,89441,804970,8049701,88546712,1062560545,

%T 13813287086,193386019205,2900790288076,46412644609217,

%U 789014958356690,14202269250420421,269843115757988000,5396862315159760001,113334108618354960022,2493350389603809120485

%N a(1)=1, a(n)=ceiling(n*(a(n-1)+1/a(n-1))).

%F a(1)=1 and for n>1, a(n)=floor((e-1/2)*n!)

%t Join[{a = 1}, Table[a = Ceiling[n*(a + 1/a)], {n, 2, 30}]]

%o (PARI) a(n)=if(n<2,1,floor((exp(1)-1/2)*n!))

%K nonn

%O 1,2

%A _Benoit Cloitre_, May 06 2003