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A082857 Inverse function of N -> N injection A082856. 4
0, 1, 0, 2, 0, 3, 0, 6, 0, 0, 0, 4, 0, 0, 0, 14, 0, 0, 0, 0, 0, 7, 0, 16, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 5, 0, 0, 0, 15, 0, 0, 0, 11, 0, 0, 0, 39, 0, 0, 0, 0, 0, 0, 0, 43, 0, 0, 0, 0, 0, 0, 0, 123, 0, 0, 0, 0, 0, 8, 0, 19, 0, 0, 0, 0, 0, 0, 0, 51, 0, 0, 0, 0, 0, 20, 0, 53, 0, 0, 0, 0, 0, 0, 0, 154, 0, 0, 0, 0, 0, 0, 0, 52, 0, 0, 0, 0, 0, 0, 0, 151, 0, 0, 0, 0, 0, 0, 0, 155 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n) = 0 for those n which do not occur as the values of A082856. All positive natural numbers occur here once.

LINKS

Table of n, a(n) for n=0..119.

A. Karttunen, Alternative Catalan Orderings (with the complete Scheme source)

PROG

(Scheme-functions showing the essential idea. For the full source, follow the "Alternative Catalan Orderings" link.)

(define A082857 (compose-funs A080300 parenthesization->binexp decode-A082856-code))

(define (decode-A082856-code code) (call-with-current-continuation (lambda (exit) (let recurse ((code code)) (cond ((zero? code) (list)) ((even? code) (exit '())) (else (let ((even-bits (A059905 (floor->exact (/ code 2)))) (odd-bits (A059906 (floor->exact (/ code 2))))) (cons (recurse odd-bits) (recurse even-bits)))))))))

CROSSREFS

A082857(A082856(n)) = n for all n. Cf. also A072634-A072637, A075173-A075174.

Sequence in context: A117175 A228086 A090482 * A208092 A081155 A130628

Adjacent sequences:  A082854 A082855 A082856 * A082858 A082859 A082860

KEYWORD

nonn

AUTHOR

Antti Karttunen May 06 2003

STATUS

approved

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Last modified June 5 23:10 EDT 2020. Contains 334858 sequences. (Running on oeis4.)