

A029471


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


141




OFFSET

1,2


COMMENTS

No other terms below 10^8.


LINKS

Table of n, a(n) for n=1..8.
Index entries for related sequences


PROG

(Python)
from itertools import count
.
def a029471():
...total = 0
...power_of_two = 1
...index_of_two = 0
...length_of_string = 0
.
...for n in count(1):
......total += (n<<length_of_string)
......if n==power_of_two:
.........power_of_two*=2
.........index_of_two += 1
.
......length_of_string += index_of_two
.
......if total % n == 0:
.........yield n
# Christian Perfect, Feb 07 2014


CROSSREFS

Cf. A029447A029470, A029471A029494, A029495A029518, A029519A029542, A061931A061954, A061955A061978
Sequence in context: A259219 A273123 A239527 * A083750 A043684 A043574
Adjacent sequences: A029468 A029469 A029470 * A029472 A029473 A029474


KEYWORD

nonn,base,hard,more


AUTHOR

Olivier Gérard


EXTENSIONS

One more term from Larry Reeves (larryr(AT)acm.org), Dec 03 2001
Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
a(7)a(8) from Max Alekseyev, May 12 2011


STATUS

approved



