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 A281014 #19 May 01 2021 07:32:55 %S A281014 8,12,14,16,17,19,23,24,25,27,28,29,30,33,35,39,47,49,51,55,57,59,61, %T A281014 64,69,73,75,77,81,83,87,89,91,93,96,101,105,107,109,112,117,120,124, %U A281014 126,129,131,133,135,137,139,141,143,145,147 %N A281014 Numbers with both prime number of 0's and prime number of 1's in their binary reflected Gray code representation. %C A281014 This sequence is the intersection of A280998 and A280999. %H A281014 Indranil Ghosh, <a href="/A281014/b281014.txt">Table of n, a(n) for n = 1..10000</a> %H A281014 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gray_code">Gray code</a>. %e A281014 27 is in the sequence as it is present in both the sequences A280998 and A280999. %t A281014 Select[Range[150], And @@ PrimeQ[DigitCount[BitXor[#, Floor[#/2]], 2]] &] (* _Amiram Eldar_, May 01 2021 *) %o A281014 (PARI) is(n)=isprime(logint(n,2)-hammingweight(bitxor(n, n>>1))+1) && isprime(hammingweight(bitxor(n, n>>1))) \\ _Charles R Greathouse IV_, Jan 13 2017 %Y A281014 Cf. A014550, A280998, A280999. %K A281014 nonn,base,easy %O A281014 1,1 %A A281014 _Indranil Ghosh_, Jan 13 2017