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

1,2

Links

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

Example

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

Mathematica

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

Prog

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

Crossrefs

Base 10 equivalent is A098952.

Sequence in context: A162860 A093006 A280236 * A138639 A082473 A325177

Adjacent sequences: A177866 A177867 A177868 * A177870 A177871 A177872

Keyword

nonn,base

Author

Grant Garcia, Dec 13 2010

Status

approved