A285726 - OEIS

A285726

a(1) = a(2) = 0; for n > 2, a(n) = A252736(n) - (1-A000035(n)).

0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 2, 0, 1, 0, 1, 1, 0, 0, 2, 1, 0, 2, 1, 0, 1, 0, 3, 1, 0, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 2, 0, 0, 3, 1, 1, 1, 1, 0, 2, 1, 2, 1, 0, 0, 2, 0, 0, 2, 4, 1, 1, 0, 1, 1, 1, 0, 3, 0, 0, 2, 1, 1, 1, 0, 3, 3, 0, 0, 2, 1, 0, 1, 2, 0, 2, 1, 1, 1, 0, 1, 4, 0, 1, 2, 2, 0, 1, 0, 2, 2, 0, 0, 3, 0, 1, 1, 3, 0, 1, 1, 1, 2, 0, 1, 3

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OFFSET

1,16

COMMENTS

Consider the binary tree illustrated in A005940: If we start from any n, computing successive iterations of A252463 until 1 is reached (i.e., we are traversing level by level towards the root of the tree, starting from that vertex of the tree where n is located), then a(n) gives the number of even numbers > 2 encountered on the path after the initial n, that is, both the penultimate 2 and also the starting n (if it was even) are excluded from the count.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..8192

FORMULA

a(1) = a(2) = 0; for n > 2, a(n) = A252736(n) - (1-A000035(n)).

PROG

(Scheme) (define (A285726 n) (if (<= n 2) 0 (- (A252736 n) (- 1 (A000035 n)))))

CROSSREFS

Cf. A000035, A005940, A252463, A252736, A285725.

Sequence in context: A350682 A375150 A319660 * A285005 A263074 A281772

Adjacent sequences: A285723 A285724 A285725 * A285727 A285728 A285729

KEYWORD

nonn

AUTHOR

Antti Karttunen, Apr 25 2017

STATUS

approved