login
In binary representation: n has the same number of 1's as the n-th prime has 0's.
4

%I #6 Nov 21 2013 12:47:50

%S 1,7,13,26,37,41,42,45,49,50,58,59,62,69,70,74,78,79,87,103,105,107,

%T 110,114,118,121,134,139,141,142,145,147,158,161,162,164,165,168,175,

%U 185,189,198,202,203,213,214,223,227,232,234,243,267,275,282,289,292

%N In binary representation: n has the same number of 1's as the n-th prime has 0's.

%C A023416(A072582(n))=A000120(a(n))=A035103(n);

%C a(n)=A049084(A072582(n)).

%e In binary representation 70='1000110' has three 1's and A000040(70)=349='101011101' has three 1's: therefore 70 is a term.

%t Select[Range[300],DigitCount[#,2,1]==DigitCount[Prime[#],2,0]&] (* _Harvey P. Dale_, May 02 2012 *)

%Y Cf. A072578, A071600, A072577.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Jun 23 2002