A005468 - OEIS

%I M0649 #17 Aug 17 2016 22:14:42

%S 1,2,3,5,7,10,16,26,36,50,71,101,161,257,417,677,937,1297,1801,2501,

%T 3551,5042,7172,10202,16262,25922,41378,66050,107170,173890,282310,

%U 458330,634350,877970,1215290,1682210,2335898,3243602,4504302,6255002

%N a(n) = 1 + a(floor(n/2))*a(ceiling(n/2)).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Alois P. Heinz, <a href="/A005468/b005468.txt">Table of n, a(n) for n = 1..5000</a>

%p a:= proc(n) option remember; `if`(n<2, n,

%p       1+(t->a(t)*a(n-t))(iquo(n, 2)))

%p     end:

%p seq(a(n), n=1..50);  # _Alois P. Heinz_, Jun 24 2016

%o (PARI) v=vector(60);v[1]=1;for(k=2,60,v[k]=v[k\2]*v[(k+1)\2]+1);v \\ _Franklin T. Adams-Watters_, Apr 22 2009

%K nonn,easy

%O 1,2

%A _Colin Mallows_

%E More terms from _Franklin T. Adams-Watters_, Apr 22 2009