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%I #14 Mar 09 2015 18:18:05
%S 1,3,13,19,21,23,25,30,44,45,47,57,60,61,71,77,98,99,101,103,107,108,
%T 110,118,121,125,158,159,178,179,184,186,187,188,209,215,218,221,237,
%U 244,246,247,248,249,251,279,287,312,334,335,346,350,359,361,362,365
%N Numbers n such that n and prime(n) have the same number of 1's in their binary representation.
%C a(n) = A049084(A072439(n)); A000120(a(n)) = A000120(A072439(n)) = A014499(n). - _Reinhard Zumkeller_, Jun 17 2002
%C A090455(a(n))=0, A000120(a(n))=A014499(a(n)).
%H Harvey P. Dale, <a href="/A071600/b071600.txt">Table of n, a(n) for n = 1..1000</a>
%e 221=11011101 in base 2, prime(221)=1381=10101100101 in base 2, both have 6 "1's" in their binary representation, hence 221 is in the sequence.
%t Select[Range[400],DigitCount[#,2,1]==DigitCount[Prime[#],2,1]&] (* _Harvey P. Dale_, Mar 09 2015 *)
%o (PARI) for(n=1,1000,s=1; if(sum(i=1,length(binary(n)), component(binary(n),i))==sum(i=1,length(binary(prime(n))), component(binary(prime(n)),i)),print1(n,",")))
%o (PARI) is(n)=hammingweight(n)==hammingweight(prime(n)) \\ _Charles R Greathouse IV_, Mar 07 2013
%Y Cf. A033549.
%K base,easy,nonn
%O 1,2
%A _Benoit Cloitre_, Jun 01 2002
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