A154450 - OEIS

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A154450

Signature permutation of a Catalan bijection: The inverse of A154449.

0, 1, 2, 3, 5, 4, 6, 7, 8, 12, 13, 11, 9, 10, 15, 14, 16, 17, 18, 19, 20, 21, 22, 31, 32, 34, 35, 36, 30, 33, 28, 24, 23, 29, 25, 26, 27, 40, 41, 39, 37, 38, 43, 42, 44, 45, 46, 47, 48, 49, 50, 52, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 87, 88, 90, 91, 92, 96, 97 (list; graph; refs; listen; history; internal format)

	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, but not starting swapping until at the right-hand side child of the root, leaving the root itself fixed. Specifically, *A154450 = psi(A154440), 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 (A154450! s) (if (pair? s) (A154452! (cdr s))) s)`
	CROSSREFS	`Inverse: A154449. a(n) = A069767(A154456(n)) = A057163(A154454(A057163(n))). Cf. A069770, A154452.` `Differs from A089850 for the first time at n=31, where a(31)=24, while A089850(31)=23.` `Sequence in context: A130375 A154122 A089850 * A154449 A122304 A122303` `Adjacent sequences: A154447 A154448 A154449 * A154451 A154452 A154453`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Jan 17 2009`

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Last modified February 17 13:28 EST 2012. Contains 206031 sequences.