A029519 Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 2 (most significant digit on right and removing all least significant zeros before concatenation).

1, 3, 7, 17, 27, 63, 92883, 1556671

Offset: 1

Author

Olivier Gérard

Keywords

• nonn
• base
• more

Comments

This sequence differs from A061955 in that all least significant zeros are removed before concatenation.

No more terms < 10^7. - Lars Blomberg, Aug 31 2011

Examples

			7 is in the sequence as the left concatenation of numbers <= 7 is 7654321 which gives 7654321 -> (111)(011)(101)(001)(11)(01)(1) base 2 -> 1111110111111_2 = 8127, and 7 divides 8127.
		

Links

• Index entries for related sequences

Crossrefs

Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.

Programs

J

mkcat =: 13 : 'y +. #. ; #:&.> |.&.#:&.> |. >:i. y'
(#~ (= mkcat"0)) >:i. 100x NB. Stephen Makdisi, May 03 2018

Mathematica

b = 2; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[IntegerDigits[IntegerReverse[#, b], b], c], b], #] &] (* Robert Price, Mar 13 2020 *)

Extensions

Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002

Additional comments and example from Larry Reeves (larryr(AT)acm.org), May 25 2001

Terms verified by Rick L. Shepherd, Feb 24 2009

1 more term from Sean A. Irvine, Oct 04 2009