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 A072578 #16 Jul 28 2025 03:11:18 %S A072578 8,16,34,44,64,65,80,106,116,128,138,140,174,178,184,193,196,209,258, %T A072578 259,260,263,264,266,272,280,288,290,314,316,325,326,327,328,330,338, %U A072578 344,385,391,402,449,514,520,521,528,544,566,570,574,578,587,590,597 %N A072578 In binary representation: k has the same number of 0's as the k-th prime has 1's. %H A072578 Amiram Eldar, <a href="/A072578/b072578.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harvey P. Dale) %F A072578 A000120(A072581(n)) = A023416(a(n)) = A014499(n). %F A072578 a(n) = A049084(A072581(n)). %e A072578 In binary representation 80 = '1010000' has five 0's and A000040(80) = 409 = '110011001' has five 1's: therefore 80 is a term. %t A072578 Select[Range[600],DigitCount[#,2,0]==DigitCount[Prime[#],2,1]&] (* _Harvey P. Dale_, Jan 07 2014 *) %Y A072578 Cf. A000120, A014499, A023416, A049084, A071600, A072577, A072579, A072581. %K A072578 nonn,base,easy %O A072578 1,1 %A A072578 _Reinhard Zumkeller_, Jun 23 2002