A079444 Number of 3-cycles in range [A014137(2n+2)..A014138(2n+2)] of permutation A057505 (= Donaghey's automorphism M).

1, 3, 7, 15, 33, 65, 133, 267

Offset

0,2

Links

Table of n, a(n) for n=0..7.

Antti Karttunen, Illustration of initial terms for trees of sizes 3..11

Robert Donaghey, Automorphisms on Catalan trees and bracketing, J. Combin. Theory, Series B, 29 (1980), 75-90.

Formula

a(n) = A079442(2n+3)/3.

Crossrefs

Cf. A079440, A079442.

Sequence in context: A307573 A134195 A365527 * A269560 A146654 A363503

Adjacent sequences: A079441 A079442 A079443 * A079445 A079446 A079447

Keyword

nonn,more

Author

Antti Karttunen, Jan 27 2003

Status

approved