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 A081092 #36 Mar 06 2025 11:00:19 %S A081092 3,5,7,11,13,17,19,31,37,41,47,59,61,67,73,79,97,103,107,109,127,131, %T A081092 137,151,157,167,173,179,181,191,193,199,211,223,227,229,233,239,241, %U A081092 251,257,271,283,307,313,331,367,379,397,409,419,421,431,433,439,443 %N A081092 Primes having a prime number of 1's in their binary representation. %C A081092 Same as primes with prime binary digit sum. %C A081092 Primes with prime decimal digit sum are A046704. %C A081092 Sum_{a(n) < x} 1/a(n) is asymptotic to log(log(log(x))) as x -> infinity; see Harman (2012). Thus the sequence is infinite. - _Jonathan Sondow_, Jun 09 2012 %C A081092 A049084(A000120(a(n))) > 0; A081091, A000215 and A081093 are subsequences. %H A081092 Reinhard Zumkeller, <a href="/A081092/b081092.txt">Table of n, a(n) for n = 1..10000</a> %H A081092 G. Harman, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL15/Harman/harman2.html">Counting Primes whose Sum of Digits is Prime</a>, J. Integer Seq., 15 (2012), Article 12.2.2. %e A081092 15th prime = 47 = '101111' with five 1's, therefore 47 is in the sequence. %p A081092 q:= n-> isprime(n) and isprime(add(i,i=Bits[Split](n))): %p A081092 select(q, [$1..500])[]; # _Alois P. Heinz_, Sep 28 2023 %t A081092 Clear[BinSumOddQ];BinSumPrimeQ[a_]:=Module[{i,s=0},s=0;For[i=1,i<=Length[IntegerDigits[a,2]],s+=Extract[IntegerDigits[a,2],i];i++ ];PrimeQ[s]]; lst={};Do[p=Prime[n];If[BinSumPrimeQ[p],AppendTo[lst,p]],{n,4!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Apr 06 2009 *) %t A081092 Select[Prime[Range[100]], PrimeQ[Apply[Plus, IntegerDigits[#, 2]]] &] (* _Jonathan Sondow_, Jun 09 2012 *) %o A081092 (Haskell) %o A081092 a081092 n = a081092_list !! (n-1) %o A081092 a081092_list = filter ((== 1) . a010051') a052294_list %o A081092 -- _Reinhard Zumkeller_, Nov 16 2012 %o A081092 (PARI) lista(nn) = {forprime(p=2, nn, if (isprime(hammingweight(p)), print1(p, ", ")););} \\ _Michel Marcus_, Jan 16 2015 %o A081092 (Python) %o A081092 from sympy import isprime %o A081092 def ok(n): return isprime(n.bit_count()) and isprime(n) %o A081092 print([k for k in range(444) if ok(k)]) # _Michael S. Branicky_, Dec 27 2023 %Y A081092 Cf. A000040, A000120, A046704, A081093. %Y A081092 Subsequence of A052294. %K A081092 nonn,base %O A081092 1,1 %A A081092 _Reinhard Zumkeller_, Mar 05 2003