A257509 Numbers n for which A257265(n) = 2; numbers for which the nearest descendant leaf in the binary beanstalk is two edges away.

0, 8, 16, 19, 32, 35, 42, 53, 64, 67, 74, 85, 89, 101, 109, 112, 128, 131, 138, 149, 153, 165, 173, 176, 184, 197, 205, 208, 221, 224, 231, 240, 256, 259, 266, 277, 281, 293, 301, 304, 312, 325, 333, 336, 349, 352, 359, 368, 375, 389, 397, 400, 413, 416, 423, 432, 445, 448, 455, 464, 470, 480, 487, 492, 512

Offset: 1

Author

Antti Karttunen, May 03 2015

Keywords

• nonn

Comments

Numbers n for which A257265(n) = 2.

Examples

			8 is present, because 12, 13 and 14 are the three leaves (terms of A055938) nearest to 8, and A011371(12) = A011371(13) = 10, A011371(14) = 11, A011371(10) = A011371(11) = 8 (thus it takes two iterations of A011371 to reach 8 from any of those three leaves). See also Paul Tek's illustration.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16385
• Paul Tek, Illustration of how natural numbers in range 0 .. 133 are organized as a binary tree in the binary beanstalk

Crossrefs

First differences: A256489.

Positions of 2's in A257265.

Subsequence of A005187.

Cf. A011371, A055938, A257508, A257264.

Programs

Haskell

a257509 n = a257509_list !! (n-1)
a257509_list = filter ((== 2) . a257265) [0..]
-- Reinhard Zumkeller, May 06 2015