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

1,2

Comments

Numbers n for which A257265(n) = 2.

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

Example

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.

Prog

(Scheme, with Antti Karttunen's IntSeq-library)
(define A257509 (MATCHING-POS 1 0 (lambda (n) (= 2 (A257265 n)))))
(Haskell)
a257509 n = a257509_list !! (n-1)
a257509_list = filter ((== 2) . a257265) [0..]
-- Reinhard Zumkeller, May 06 2015

Crossrefs

First differences: A256489.

Positions of 2's in A257265.

Subsequence of A005187.

Cf. A011371, A055938, A257508, A257264.

Sequence in context: A092456 A232724 A260409 * A232570 A029522 A033309

Adjacent sequences: A257506 A257507 A257508 * A257510 A257511 A257512

Keyword

nonn

Author

Antti Karttunen, May 03 2015

Status

approved