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%I #21 May 01 2021 07:32:44
%S 7,8,12,14,15,16,17,19,23,24,25,27,28,29,30,33,34,35,36,38,39,40,44,
%T 46,47,49,50,51,52,54,55,57,58,59,61,63,64,66,68,69,70,72,73,75,76,77,
%U 78,80,81,83,87,88,89,91,92,93,94,96,98,100,101,102,104,105,107
%N Numbers with a prime number of 0's in their binary reflected Gray code representation.
%H Indranil Ghosh, <a href="/A280999/b280999.txt">Table of n, a(n) for n = 1..10000</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Gray_code">Gray code</a>.
%e 27 is in the sequence because the binary reflected Gray Code representation of 27 is 10110 which has 2 0's and 2 is prime.
%t Select[Range[100], PrimeQ[DigitCount[BitXor[#, Floor[#/2]], 2, 0]] &] (* _Amiram Eldar_, May 01 2021 *)
%o (PARI) is(n)=isprime(logint(n,2)-hammingweight(bitxor(n, n>>1))+1) \\ _Charles R Greathouse IV_, Jan 13 2017
%Y Cf. A014550, A144754, A280998.
%K nonn,base,easy
%O 1,1
%A _Indranil Ghosh_, Jan 12 2017