This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A072579 #13 Jul 28 2025 03:13:08 %S A072579 1,7,13,26,37,41,42,45,49,50,58,59,62,69,70,74,78,79,87,103,105,107, %T A072579 110,114,118,121,134,139,141,142,145,147,158,161,162,164,165,168,175, %U A072579 185,189,198,202,203,213,214,223,227,232,234,243,267,275,282,289,292 %N A072579 In binary representation: k has the same number of 1's as the k-th prime has 0's. %H A072579 Amiram Eldar, <a href="/A072579/b072579.txt">Table of n, a(n) for n = 1..10000</a> %F A072579 A023416(A072582(n)) = A000120(a(n)) = A035103(n). %F A072579 a(n) = A049084(A072582(n)). %e A072579 In binary representation 70 = '1000110' has three 1's and A000040(70) = 349 = '101011101' has three 1's: therefore 70 is a term. %t A072579 Select[Range[300],DigitCount[#,2,1]==DigitCount[Prime[#],2,0]&] (* _Harvey P. Dale_, May 02 2012 *) %Y A072579 Cf. A000120, A023416, A035103, A049084, A071600, A072577, A072578, A072582. %K A072579 nonn,base,easy %O A072579 1,2 %A A072579 _Reinhard Zumkeller_, Jun 23 2002