A089880 - OEIS

%I #6 Mar 31 2012 14:02:18

%S 1,1,2,3,10,22,76,217,750,2438,8524,29414,104468,371516,1338936,

%T 4847637,17685270,64823110,238843660,883634026,3282152588,12233141908,

%U 45741634536,171529836218,644953425740,2430973304732,9183681736376

%N Number of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A069772.

%C The number of orbits to which the corresponding automorphism(s) partitions the set of A000108(n) binary trees with n internal nodes.

%H A. Karttunen, <a href="/A089408/a089408.c.txt">C-program for computing the initial terms of this sequence</a>

%F a(n) = (A000108(n)+A089849(n))/2

%o (Scheme) (define (A089880 n) (/ (+ (A000108 n) (A089849 n)) 2))

%K nonn,easy

%O 0,3

%A _Antti Karttunen_, Nov 29 2003