A177869 Integers divisible by their number of digits in binary.

1, 2, 6, 8, 12, 20, 25, 30, 36, 42, 48, 54, 60, 70, 77, 84, 91, 98, 105, 112, 119, 126, 128, 136, 144, 152, 160, 168, 176, 184, 192, 200, 208, 216, 224, 232, 240, 248, 261, 270, 279, 288, 297, 306, 315, 324, 333, 342, 351, 360, 369, 378, 387, 396, 405

Offset: 1

Author

Grant Garcia, Dec 13 2010

Keywords

• nonn
• base

Examples

			105 is 1101001 in base 2 (length of 7); 105 / 7 is 15.
		

Links

• Daniel Arribas, Table of n, a(n) for n = 1..1000

Crossrefs

Base 10 equivalent is A098952.

Programs

Haskell

base_weight b g n | n == 0 = 0 | otherwise = (base_weight b g (n `div` b)) + (g $ n `mod` b)
interesting b g = filter f [1..] where f n = n `mod` (base_weight b g n) == 0
bin_interesting g = interesting 2 g
weights l n | (n >=0) && ((length l) > fromInteger n) = l !! fromInteger n | otherwise = 0
cnst = weights [1, 1]
let sequence = bin_interesting cnst -- Victor S. Miller, Oct 17 2011

Mathematica

Select[Range[410], IntegerQ[#/Length[IntegerDigits[#, 2]]] &] (* Alonso del Arte, Dec 13 2010 *)

PARI

for(d=1, 9, forstep(n=(2^(d-1)+d-1)\d*d, 2^d-1, d, print1(n", "))) \\ Charles R Greathouse IV, Oct 17 2011

Python

import math
for n in range(1, 1000):
    if not n % int(math.log(n, 2) + 1): print(n) # Garcia