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 A085448 #13 Dec 14 2019 08:09:10 %S A085448 23,29,43,53,71,83,89,101,113,139,149,163,197,263,269,277,281,293,311, %T A085448 317,337,347,349,353,359,373,389,401,449,461,467,523,547,571,593,599, %U A085448 619,643,673,683,691,739,773,797,811,821,839,853,857,881,907,937,977 %N A085448 Primes having a semiprime number of 1's in their binary representation. %C A085448 Sequence of least prime with the number of 1's in its binary representation equal to n-th semiprime is: 23,311,991,2039,73727,63487,4128767,... What is the prime corresponding to 22? %H A085448 Amiram Eldar, <a href="/A085448/b085448.txt">Table of n, a(n) for n = 1..10000</a> %e A085448 The prime 43 = '101011' has four 1's and so is a term. %t A085448 seqQ[n_] := PrimeQ[n] && PrimeOmega[DigitCount[n, 2, 1]] == 2; Select[Range[1000], seqQ] (* _Amiram Eldar_, Dec 14 2019 *) %Y A085448 Cf. A001358, A081092. %K A085448 easy,nonn,base %O A085448 1,1 %A A085448 _Jason Earls_, Aug 14 2003