A079442 Number of fixed points in range [A014137(n-1)..A014138(n)] of permutation A071663.

1, 1, 0, 3, 0, 9, 0, 21, 0, 45, 0, 99, 0, 195, 0, 399, 0, 801, 0, 1599, 0, 3213, 0

Offset

0,4

Links

Table of n, a(n) for n=0..22.

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

Antti Karttunen, C-program for counting the initial terms of this sequence

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

L. W. Shapiro, The cycle of six, The Fibonacci Quarterly, 17(3), (1979), 253-259.

Formula

For all n >= 0, a(2n+3)/3 = A079444(n).

Crossrefs

Cf. A057505, A071663, A079438, A079441, A079443, A079444.

Occurs in A073202 as row 176609070820803.

Sequence in context: A395954 A164597 A167295 * A254006 A321329 A016645

Adjacent sequences: A079439 A079440 A079441 * A079443 A079444 A079445

Keyword

nonn,more,hard

Author

Antti Karttunen, Jan 27 2003

Extensions

Name corrected by Antti Karttunen, Dec 13 2017

a(19)-a(22) from Vjeran Crnjak, Apr 15 2026

Status

approved