id:A129607 - OEIS Search Results

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Signature-permutation of a Catalan automorphism: swap the left and right subtree of degree 2 general trees.

+0
2

0, 1, 2, 3, 4, 6, 5, 7, 8, 9, 10, 11, 16, 19, 14, 15, 12, 17, 18, 13, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 44, 47, 33, 53, 56, 60, 37, 38, 39, 43, 52, 42, 40, 31, 45, 46, 32, 48, 49, 50, 51, 41, 34, 54, 55, 35, 57, 58, 59, 36, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`Otherwise like automorphism A072796, except that this involution exchanges the two leftmost subtrees of a general tree ONLY when the degree of the tree is two. Automorphism A129608 = SPINE(A129607) = ENIPS(A129607). See the definitions given in A122203 and A122204.`
	LINKS	`A. Karttunen, Table of n, a(n) for n = 0..2055` `A. Karttunen, Prolog-program which illustrates the construction of this and similar nonrecursive Catalan automorphisms.` `Index entries for signature-permutations of Catalan automorphisms`
	PROGRAM	`(Constructive and destructive Scheme implementation of this automorphism. These act on S-expressions, i.e. list-structures:)` `(define (A129607 s) (if (= 2 (length s)) (A072796 s) s))` `(define (A129607! s) (if (= 2 (length s)) (A072796! s)) s)`
	CROSSREFS	`Row 3608 of A089840.` `Adjacent sequences: A129604 A129605 A129606 this_sequence A129608 A129609 A129610` `Sequence in context: A102284 A100700 A066115 this_sequence A130340 A130339 A058812`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), May 22 2007`

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Last modified October 6 12:54 EDT 2008. Contains 144667 sequences.

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