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Numbers k such that the number of 1's in the binary representation of k divides 2^k+1.
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%I #17 May 13 2022 04:55:03

%S 1,2,4,7,8,11,13,16,19,21,25,32,35,37,41,49,62,64,67,69,73,81,94,97,

%T 110,118,122,128,131,133,137,145,158,161,174,182,186,193,206,214,218,

%U 230,234,242,256,259,261,265,273,286,289,302,310,314,321,334,342,346

%N Numbers k such that the number of 1's in the binary representation of k divides 2^k+1.

%H Amiram Eldar, <a href="/A074204/b074204.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[350],Divisible[2^#+1,DigitCount[#,2,1]]&] (* _Harvey P. Dale_, Feb 19 2011 *)

%o (PARI) isok(n) = !((2^n+1) % hammingweight(n)); \\ _Michel Marcus_, Nov 29 2013

%Y Cf. A000051, A000120.

%K base,easy,nonn

%O 1,2

%A _Benoit Cloitre_, Sep 17 2002