A154452 - OEIS

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A154452

Signature permutation of a Catalan bijection: The inverse of A154451.

0, 1, 3, 2, 7, 8, 6, 4, 5, 17, 18, 20, 21, 22, 16, 19, 14, 10, 9, 15, 11, 12, 13, 45, 46, 48, 49, 50, 54, 55, 57, 58, 59, 61, 62, 63, 64, 44, 47, 53, 56, 60, 42, 51, 38, 26, 27, 37, 25, 23, 24, 43, 52, 39, 29, 28, 40, 30, 31, 32, 41, 33, 34, 35, 36, 129, 130, 132, 133, 134

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OFFSET

0,3

COMMENTS

This automorphism of rooted plane binary trees switches the two descendant trees for every other vertex as it descends along the 111... ray, starting swapping already at the root. Specifically, *A154452 = psi(A154442), where the isomorphism psi is given in A153141 (see further comments there).

LINKS

A. Karttunen, Table of n, a(n) for n = 0..2055

Index entries for signature-permutations of Catalan automorphisms

PROG

(Scheme function, destructive implementation of this automorphism acting on S-expressions:) (define (*A154452! s) (cond ((pair? s) (*A069770! s) (*A154450! (cdr s)))) s)

CROSSREFS

Inverse: A154451. a(n) = A069767(A154454(n)) = A057163(A154456(A057163(n))). Cf. A069770, A154450.

Sequence in context: A154455 A082345 A122327 * A130999 A129611 A154456

Adjacent sequences: A154449 A154450 A154451 * A154453 A154454 A154455

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jan 17 2009

STATUS

approved