

A280999


Numbers with a prime number of 0's in their binary reflected Gray code representation.


4



7, 8, 12, 14, 15, 16, 17, 19, 23, 24, 25, 27, 28, 29, 30, 33, 34, 35, 36, 38, 39, 40, 44, 46, 47, 49, 50, 51, 52, 54, 55, 57, 58, 59, 61, 63, 64, 66, 68, 69, 70, 72, 73, 75, 76, 77, 78, 80, 81, 83, 87, 88, 89, 91, 92, 93, 94, 96, 98, 100, 101, 102, 104, 105, 107
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..10000
Wikipedia, Gray code.


EXAMPLE

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.


MATHEMATICA

Select[Range[100], PrimeQ[DigitCount[BitXor[#, Floor[#/2]], 2, 0]] &] (* Amiram Eldar, May 01 2021 *)


PROG

(PARI) is(n)=isprime(logint(n, 2)hammingweight(bitxor(n, n>>1))+1) \\ Charles R Greathouse IV, Jan 13 2017


CROSSREFS

Cf. A014550, A144754, A280998.
Sequence in context: A106630 A050798 A260628 * A024706 A050901 A105832
Adjacent sequences: A280996 A280997 A280998 * A281000 A281001 A281002


KEYWORD

nonn,base,easy


AUTHOR

Indranil Ghosh, Jan 12 2017


STATUS

approved



