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A084561 Numbers with a square number of 1's in their binary expansion. 2


%S 0,1,2,4,8,15,16,23,27,29,30,32,39,43,45,46,51,53,54,57,58,60,64,71,

%T 75,77,78,83,85,86,89,90,92,99,101,102,105,106,108,113,114,116,120,

%U 128,135,139,141,142,147,149,150,153,154,156,163,165,166,169,170,172,177,178

%N Numbers with a square number of 1's in their binary expansion.

%C Begins to differ from A084345 at the 22nd term.

%C There are A003099(n) terms with at most n bits, so a(n) is n sqrt log n times a bounded function of n (which does not tend toward a limit). - _Charles R Greathouse IV_, Mar 26 2013

%H Amiram Eldar, <a href="/A084561/b084561.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[0,178],IntegerQ[Sqrt[Count[IntegerDigits[#,2],1]]]&] (* _Jayanta Basu_, May 24 2013 *)

%o (PARI) is(n)=issquare(hammingweight(n)) \\ _Charles R Greathouse IV_, Mar 26 2013

%Y Cf. A001969, A000069, A052294, A084345.

%K easy,nonn,base

%O 1,3

%A _Jason Earls_, Jun 27 2003

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Last modified September 29 06:29 EDT 2020. Contains 337425 sequences. (Running on oeis4.)