A029495 Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 2 (most significant digit on right).

1, 5, 337

Offset

1,2

Comments

This sequence differs from A061931 in that all least significant zeros are kept during concatenation.

No more terms < 10^7. - Lars Blomberg, Oct 01 2011

Links

Table of n, a(n) for n=1..3.

Index entries for related sequences

Example

12345 -> (1)(01)(11)(001)(101) base 2 -> 10111001101 base 2 = 1485 and 5 divides 1485.

Mathematica

b = 2; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, Reverse[IntegerDigits[#, b]]], b], #] &] (* Robert Price, Mar 12 2020 *)

Prog

(PARI) is(n) = my(t=[]); for(k=1, n, t=concat(t, Vecrev(binary(k)))); if(Mod(subst(Pol(t), x, 2), n)==0, return(1), return(0)) \\ Felix Fröhlich, Jul 06 2017

Crossrefs

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

Sequence in context: A316446 A316128 A317434 * A086900 A200002 A265921

Adjacent sequences: A029492 A029493 A029494 * A029496 A029497 A029498

Keyword

nonn,base,bref

Author

Olivier Gérard

Extensions

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

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

Status

approved