A253554 a(1) = 1, a(2n) = n, a(2n+1) = A250470(2n+1).

1, 1, 2, 2, 3, 3, 5, 4, 4, 5, 7, 6, 11, 7, 6, 8, 13, 9, 17, 10, 8, 11, 19, 12, 9, 13, 10, 14, 23, 15, 29, 16, 12, 17, 15, 18, 31, 19, 14, 20, 37, 21, 41, 22, 16, 23, 43, 24, 25, 25, 18, 26, 47, 27, 21, 28, 20, 29, 53, 30, 59, 31, 22, 32, 27, 33, 61, 34, 24, 35, 67, 36, 71, 37, 26, 38, 35, 39, 73, 40, 28, 41, 79, 42, 33, 43, 30

Offset: 1

Author

Antti Karttunen, Jan 12 2015

Keywords

• nonn

Comments

Divide the even numbers by two, and for odd numbers n >= 3, a(n) = A078898(n)-th number k for which A055396(k) = A055396(n)-1.

For any number n >= 2 in binary trees A252753 and A252755, a(n) gives the number which is the parent of n.

Links

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

Crossrefs

Bisections: A000027 and A250472.

Cf. A253555 (the number of iterations needed to reach 1 from n).

Cf. A055396, A078898, A250470, A252753, A252755.

Differs from A252463 for the first time at n=21, where a(21) = 8, while A252463(21) = 10.

Programs

Scheme

(define (A253554 n) (cond ((<= n 1) n) ((even? n) (/ n 2)) (else (A250470 n))))

Formula

a(1) = 1, a(2n) = n, a(2n+1) = A250470(2n+1).