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

Offset: 1

Author

Antti Karttunen, Apr 25 2017

Keywords

• nonn

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

Crossrefs

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

Programs

Scheme

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

Formula

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