

A029519


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


141




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. A029447A029470, A029471A029494, A029495A029518, A029519A029542, A061931A061954, A061955A061978.
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



