A292204 Primes as they appear in A006068.

3, 2, 7, 5, 13, 11, 31, 29, 17, 19, 23, 61, 59, 53, 37, 47, 41, 43, 127, 113, 97, 103, 101, 109, 107, 67, 71, 79, 73, 89, 83, 251, 241, 227, 229, 239, 233, 193, 199, 197, 223, 211, 131, 137, 139, 157, 151, 149, 191, 179, 181, 163, 167, 173, 509, 499, 503, 487, 491, 449, 463, 461

Offset: 1

Author

Robert G. Wilson v, Sep 11 2017

Keywords

• nonn

Comments

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.

Crossrefs

Cf. A006068, A292203, A292205.

Programs

Mathematica

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

PARI

grayinto(n) = my(B=n); for(k=1, log(n+1)\log(2), B=bitxor(B, n\2^k)); B;
lista(nn) = for (n=1, nn, if (isprime(p=grayinto(n)), print1(p, ", "))); \\ Michel Marcus, Oct 10 2017

Python

from itertools import count, islice
from sympy import isprime
def A292204_gen(): # generator of terms
    for n in count(0):
        k, m = n, n>>1
        while m > 0:
            k ^= m
            m >>= 1
        if isprime(k):
            yield k
A292204_list = list(islice(A292204_gen(),30)) # Chai Wah Wu, Jun 29 2022