id:A130340 - OEIS Search Results

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Signature permutation of a Catalan automorphism: swap the two leftmost subtrees of general trees, if the root degree (A057515(n)) is even.

+0
3

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, 37, 29, 30, 44, 47, 33, 53, 56, 60, 28, 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	`This is a self-inverse automorfism (an involution). Can be used to construct A130373.`
	LINKS	`A. Karttunen, Table of n, a(n) for n = 0..2055` `Index entries for signature-permutations of Catalan automorphisms`
	PROGRAM	`(Destructive Scheme implementation of this automorphism, which acts on S-expressions, i.e. list-structures:)` `(define (A130340! s) (if (even? (length s)) (A072796! s)) s)`
	CROSSREFS	`Cf. a(n) = A057508(A130339(A057508(n))) = A057164(A130339(A057164(n))). a(n) = A072796(n), if A057515(n) mod 2 = 0, otherwise a(n)=n.` `Adjacent sequences: A130337 A130338 A130339 this_sequence A130341 A130342 A130343` `Sequence in context: A100700 A066115 A129607 this_sequence A130339 A058812 A072796`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Jun 05 2007`

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Last modified October 13 20:18 EDT 2008. Contains 145016 sequences.

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