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A117890
Numbers n such that number of non-leading 0's in binary representation of n divides n.
2
2, 4, 5, 6, 10, 11, 12, 13, 14, 16, 18, 22, 23, 24, 26, 27, 28, 29, 30, 36, 40, 42, 46, 47, 48, 54, 55, 58, 59, 60, 61, 62, 65, 75, 76, 78, 80, 84, 88, 90, 94, 95, 99, 100, 102, 104, 105, 108, 110, 111, 112, 114, 118, 119, 120, 122, 123, 124, 125, 126, 132, 140, 144, 145
OFFSET
1,1
COMMENTS
Contains primes of A095078(n) as a subset. Intersection of a(n) with A049445(n) is A117891(n). - R. J. Mathar, Apr 03 2006
LINKS
FORMULA
a(n)<=A117891(n) - R. J. Mathar, Apr 03 2006
a(n) mod A023416(a(n)) = 0. - Reinhard Zumkeller, Nov 22 2007
EXAMPLE
24 is 11000 in binary. This binary representation has three 0's and 3 divides 24. So 24 is in the sequence.
PROG
(C) #include <stdio.h> int main(int argc, char *argv[]) { for(int n=1; n< 500; n++) { int digs=0; int nshifted=n; while(nshifted) { digs += 1- nshifted & 1; nshifted >>= 1; } if ( digs) if( n % digs == 0 ) printf("%d, ", n); } } - R. J. Mathar, Apr 03 2006
(Haskell)
a117890 n = a117890_list !! (n-1)
a117890_list = [x | x <- [1..], let z = a023416 x, z > 0, mod x z == 0]
-- Reinhard Zumkeller, Mar 31 2015
CROSSREFS
Cf. A023416.
Sequence in context: A325558 A140779 A348937 * A108853 A257085 A334736
KEYWORD
easy,nonn
AUTHOR
Leroy Quet, Mar 30 2006
EXTENSIONS
More terms from R. J. Mathar, Apr 03 2006
STATUS
approved