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

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

Offset

1,2

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

Links

Table of n, a(n) for n=1..8.

Index entries for related sequences

Example

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.

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A041663 A042825 A076033 * A045424 A106968 A191081

Adjacent sequences: A029516 A029517 A029518 * A029520 A029521 A029522

Keyword

nonn,base,more

Author

Olivier Gérard

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

Status

approved