A257507 Row 2 of A257264: a(n) = A011371(A055938(n)).

1, 3, 4, 7, 10, 10, 11, 15, 18, 18, 22, 23, 25, 25, 26, 31, 34, 34, 38, 39, 41, 41, 46, 47, 49, 50, 54, 54, 56, 56, 57, 63, 66, 66, 70, 71, 73, 73, 78, 79, 81, 82, 86, 86, 88, 88, 94, 95, 97, 98, 102, 102, 104, 105, 110, 110, 113, 116, 117, 117, 119, 119, 120, 127, 130, 130, 134, 135, 137, 137, 142, 143, 145, 146

Offset: 1

Author

Antti Karttunen, May 03 2015

Keywords

• nonn

Comments

The sequence gives the parent node of each leaf-vertex (A055938) in binary beanstalk.

Examples

			Terms of A055938 are the leaf-nodes in Paul Tek's illustration. This sequence gives the corresponding parent-node (in that illustration a node immediately below where the arrow points), for each term of A055938[1..]: 2, 5, 6, 9, 12, 13, 14, ...
As A055938(4) = 9, and 9's parent node is 7 (because A011371(9) = 7), a(4) = 7.
As A055938(5) = 12, and 12's parent node is 10, a(5) = 10.
As A055938(6) = 13, and 13's parent node is 10, a(6) = 10.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Paul Tek, Illustration of how natural numbers in range 0 .. 133 are organized as a binary tree in the binary beanstalk

Crossrefs

Row 2 of A257264.

Cf. A011371, A055938.

Cf. A257508 (same sequence with duplicates removed), A257512 (the terms which occur twice).

Programs

Scheme

(define (A257507 n) (A011371 (A055938 n)))

Formula

a(n) = A011371(A055938(n)).