cp's OEIS Frontend

A200044 Starting with a(1)=1, a(n) = n*a(n-1) if n>= a(n-1), otherwise a(n) = a(n-1)-n.

%I A200044 #18 Oct 20 2016 09:45:50
%S A200044 1,2,6,2,10,4,28,20,11,1,11,132,119,105,90,74,57,39,20,400,379,357,
%T A200044 334,310,285,259,232,204,175,145,114,82,49,15,525,489,452,414,375,335,
%U A200044 294,252,209,165,120,74,27,1296,1247,1197,1146,1094
%N A200044 Starting with a(1)=1, a(n) = n*a(n-1) if n>= a(n-1), otherwise a(n) = a(n-1)-n.
%H A200044 Ivan Neretin, <a href="/A200044/b200044.txt">Table of n, a(n) for n = 1..9119</a>
%e A200044 Start with 1, then as 2 is bigger than 1, 1 * 2 = 2. As n=3 is bigger than 2, 2 * 3 = 6. As n=4 is smaller than 6, 6 - 4 = 2, then 2 * 5 = 10, then 10 - 6 = 4, then 4 * 7 = 28, etc
%p A200044 A200044 := proc(n)
%p A200044     option remember;
%p A200044     if n = 1 then
%p A200044         1;
%p A200044     elif n >= procname(n-1) then
%p A200044         n*procname(n-1) ;
%p A200044     else
%p A200044         procname(n-1)-n ;
%p A200044     end if;
%p A200044 end proc:
%p A200044 seq(A200044(n),n=1..80) ; # _R. J. Mathar_, Jan 28 2012
%t A200044 a = {1}; Do[AppendTo[a, If[a[[-1]] <= n, a[[-1]]*n, a[[-1]] - n]], {n, 2, 52}]; a (* _Ivan Neretin_, May 20 2015 *)
%t A200044 nxt[{n_,a_}]:={n+1,If[n+1>=a,a(n+1),a-n-1]}; NestList[nxt,{1,1},60][[All,2]] (* _Harvey P. Dale_, Oct 20 2016 *)
%K A200044 nonn,easy
%O A200044 1,2
%A A200044 _Rodolfo Kurchan_, Nov 12 2011