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%I #22 Jun 30 2022 02:06:56
%S 3,2,6,5,13,9,30,29,26,22,21,57,49,50,53,38,45,41,125,122,113,117,98,
%T 110,65,70,69,77,73,94,85,253,241,242,230,229,233,194,197,201,221,217,
%U 213,129,134,133,157,149,189,185,177,181,161,173,510,506,502,501
%N prime(n) Gray code decoding.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GrayCode.html">Gray code</a>.
%F a(n) = A006068(A000040(n)). - _Joerg Arndt_, Nov 01 2020
%e f(x) = gray_code_to_natural(x) = A006068(x),
%e a(1) = f(2) = 3,
%e a(2) = f(3) = 2,
%e a(3) = f(5) = 6,
%e a(4) = f(7) = 5,
%e a(5) = f(11) = 13.
%t Array[BitXor @@ Table[Floor[#/2^m], {m, 0, Floor@ Log2[#]}] &@ Prime[#] &, 58] (* _Michael De Vlieger_, Nov 05 2020 *)
%o (Ruby) require 'prime'
%o values = Prime.first(50).map { |x| x ^= x >> 16; x ^= x >> 8; x ^= x >> 4; x ^= x >> 2; x ^= x >> 1; x }
%o p values
%o (Python)
%o from sympy import prime
%o def A338524(n):
%o k = prime(n)
%o m = k>>1
%o while m > 0:
%o k ^= m
%o m >>= 1
%o return k # _Chai Wah Wu_, Jun 29 2022
%Y Cf. A000040, A006068, A143292 (Gray code of prime(n)).
%K nonn
%O 1,1
%A _Simon Strandgaard_, Nov 01 2020
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