A180537 Primes that become a different prime under the mapping 2 <=> 7.

2, 7, 23, 29, 73, 79, 223, 233, 239, 251, 269, 521, 571, 733, 739, 751, 769, 773, 1259, 1283, 1289, 1759, 1783, 1789, 1823, 1873, 2029, 2039, 2069, 2179, 2203, 2273, 2293, 2309, 2333, 2351, 2371, 2393, 2411, 2459, 2549, 2579, 2591, 2671, 2699, 2711, 2713

Offset: 1

Author

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Keywords

• base
• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..1694
• Index to Primes, Primes that become a different prime under some mapping.

Crossrefs

Cf. A171036, A175791, A180517 thru A180559, A175789, A180560, A180561.

Programs

Mathematica

fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 2] || MemberQ[id, 7]) && PrimeQ[ FromDigits[ id /. {2 -> 7, 7 -> 2}] ]]; Select[ Prime@ Range@ 400, fQ]