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A089402 Number of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A089864. 3
1, 1, 2, 3, 8, 22, 68, 217, 720, 2438, 8412, 29414, 104048, 371516, 1337352, 4847637, 17679264, 64823110, 238820780, 883634026, 3282065072, 12233141908, 45741298616, 171529836218, 644952132448, 2430973304732, 9183676744088 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

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

LINKS

Table of n, a(n) for n=0..26.

A. Karttunen, C-program for computing the initial terms of this sequence

FORMULA

a(n) = (A000108(n)+A089408(n))/2

PROG

(Scheme) (define (A089402 n) (* (/ 1 2) (+ (A000108 n) (A089408 n))))

CROSSREFS

Sequence in context: A098119 A049959 A006545 * A127940 A006796 A241904

Adjacent sequences:  A089399 A089400 A089401 * A089403 A089404 A089405

KEYWORD

nonn,easy

AUTHOR

Antti Karttunen, Nov 29 2003

STATUS

approved

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Last modified July 23 00:43 EDT 2019. Contains 325228 sequences. (Running on oeis4.)