A292204 - OEIS

%I #20 Jun 30 2022 08:39:56

%S 3,2,7,5,13,11,31,29,17,19,23,61,59,53,37,47,41,43,127,113,97,103,101,

%T 109,107,67,71,79,73,89,83,251,241,227,229,239,233,193,199,197,223,

%U 211,131,137,139,157,151,149,191,179,181,163,167,173,509,499,503,487,491,449,463,461

%N Primes as they appear in A006068.

%C a(n) is the i-th prime (as it appears in A000040) for i = 2, 1, 4, 3, 6, 5, 9, 10, 11, 8, 7, 15, 17, 18, 16, 14, etc.

%t f[n_] := BitXor @@ Table[ Floor[n/2^m], {m, 0, Floor[Log2@ n]}]; Select[ Array[f, 300], PrimeQ]

%o (PARI) grayinto(n) = my(B=n); for(k=1, log(n+1)\log(2), B=bitxor(B, n\2^k)); B;

%o lista(nn) = for (n=1, nn, if (isprime(p=grayinto(n)), print1(p, ", "))); \\ _Michel Marcus_, Oct 10 2017

%o (Python)

%o from itertools import count, islice

%o from sympy import isprime

%o def A292204_gen(): # generator of terms

%o     for n in count(0):

%o         k, m = n, n>>1

%o         while m > 0:

%o             k ^= m

%o             m >>= 1

%o         if isprime(k):

%o             yield k

%o A292204_list = list(islice(A292204_gen(),30)) # _Chai Wah Wu_, Jun 29 2022

%Y Cf. A006068, A292203, A292205.

%K nonn

%O 1,1

%A _Robert G. Wilson v_, Sep 11 2017