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A154452
Signature permutation of a Catalan bijection: The inverse of A154451.
6
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
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).
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
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 17 2009
STATUS
approved