id:A071651 - OEIS Search Results

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Permutation of natural numbers induced by reranking plane binary trees given in the standard lexicographic order (A014486) with an "arithmetic global ranking algorithm", using A061579 as the packing bijection N X N -> N.

+0
9

0, 1, 2, 3, 4, 7, 5, 6, 10, 11, 29, 16, 22, 56, 8, 12, 9, 15, 36, 14, 21, 28, 66, 67, 436, 137, 254, 1597, 37, 79, 46, 121, 667, 106, 232, 407, 2212, 17, 38, 23, 30, 68, 13, 18, 20, 78, 465, 44, 153, 276, 1653, 19, 25, 27, 45, 91, 35, 55, 136, 703, 77, 120, 253, 435, 2278 (list; graph; listen)

	OFFSET	`0,3`
	LINKS	`A. Karttunen, Gatomorphisms` `Index entries for sequences that are permutations of the natural numbers`
	PROGRAM	`(Scheme functions below show the essential idea. For a complete source, follow the "Gatomorphisms" link.)` `(define lexrank->arithrankA061579 (lexrank->arithrank-bijection packA061579))` `(define (lexrank->arithrank-bijection packfun) (lambda (n) (rank-bintree (binexp->parenthesization (A014486 n)) packfun)))` `(define (rank-bintree bt packfun) (cond ((not (pair? bt)) 0) (else (1+ (packfun (rank-bintree (car bt) packfun) (rank-bintree (cdr bt) packfun))))))` `(define (packA061579 x y) (/ (+ (expt (+ x y) 2) (* 3 x) y) 2))`
	CROSSREFS	`Inverse permutation: A071652. Cf. also A014486, A061579, A071653, A071654.` `Sequence in context: A125978 A014321 A072767 this_sequence A072658 A099864 A056535` `Adjacent sequences: A071648 A071649 A071650 this_sequence A071652 A071653 A071654`
	KEYWORD	`nonn`
	AUTHOR	`Antti Karttunen May 30 2002`

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

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