A209286 - OEIS

%I #40 Apr 13 2014 11:30:51

%S 0,1,1,1,3,5,9,27,77,329,2435,27845,829289,68634299,23160214349,

%T 56940830227049,1589642017432217699,1318763422910513770158149,

%U 90515537555154997905172366725449,2096361748201801549831377117539292825822299

%N a(n) = a(n-1) + (1+a(n-2))*a(n-3) for n>1, a(1) = 1, a(n) = 0 for n<1.

%H Alois P. Heinz, <a href="/A209286/b209286.txt">Table of n, a(n) for n = 0..30</a>

%F a(n) = a(n-1) + (1+a(n-2))*a(n-3) for n>1, a(1) = 1, a(n) = 0 for n<1.

%p a:= proc(n) a(n):= `if`(n<1, 0,

%p       `if`(n=1, 1, a(n-1) +(1+a(n-2))*a(n-3)))

%p     end:

%p seq(a(n), n=0..20);  # _Alois P. Heinz_, Feb 20 2013

%t Rest[RecurrenceTable[{a[-1]==a[0]==0,a[1]==1,a[n]==a[n-1]+(1+a[n-2]) a[n-3]},a,{n,20}]] (* _Harvey P. Dale_, Apr 13 2014 *)

%K nonn

%O 0,5

%A _Chris Kunferman_, Feb 17 2013