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A209641 A014486-codes for rooted plane trees where non-leaf branches can occur only as the leftmost branch of any level, but nowhere else. Sorted into ascending order. 6
0, 2, 10, 12, 42, 50, 52, 56, 170, 202, 210, 212, 226, 228, 232, 240, 682, 810, 842, 850, 852, 906, 914, 916, 930, 932, 936, 962, 964, 968, 976, 992, 2730, 3242, 3370, 3402, 3410, 3412, 3626, 3658, 3666, 3668, 3722, 3730, 3732, 3746, 3748, 3752, 3850, 3858, 3860, 3874, 3876, 3880, 3906, 3908, 3912, 3920, 3970, 3972 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..32767

PROG

(Scheme): (define (member_of_A209641? n) (let loop ((n n) (lev 0)) (cond ((zero? n) (zero? lev)) ((< lev 0) #f) ((even? n) (loop (/ n 2) (+ lev 1))) ((and (odd? (/ (-1+ n) 2)) (even? (/ (-1+ (/ (-1+ n) 2)) 2)) (not (zero? (/ (-1+ (/ (-1+ n) 2)) 2)))) #f) (else (loop (/ (- n 1) 2) (- lev 1))))))

(define A209641 (MATCHING-POS 0 0 member_of_A209641?)) ;; MATCHING-POS in AK's Scheme-SeqFun-Transform package.

CROSSREFS

A209640(a(n)) = n for all n. a(n) = A014486(A209643(n)). Sequence A209642 sorted into ascending order with permutation A209862, i.e.  a(n) = A209642(A209862(n)).

Sequence in context: A216649 A071162 A075165 * A209642 A061855 A144145

Adjacent sequences:  A209638 A209639 A209640 * A209642 A209643 A209644

KEYWORD

nonn

AUTHOR

Antti Karttunen, Mar 24 2012

STATUS

approved

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Last modified June 16 14:16 EDT 2021. Contains 345057 sequences. (Running on oeis4.)