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Primes that become a different prime under the mapping 4 <=> 5.
1

%I #11 Oct 30 2023 17:11:54

%S 43,53,241,251,349,359,409,421,457,463,487,499,509,521,547,563,587,

%T 599,643,653,1249,1259,1423,1453,1459,1471,1483,1523,1543,1549,1571,

%U 1583,2143,2153,2341,2347,2351,2357,2441,2447,2459,2549,2551,2557,2647,2657

%N Primes that become a different prime under the mapping 4 <=> 5.

%H Robert Price, <a href="/A180546/b180546.txt">Table of n, a(n) for n = 1..2141</a>

%H <a href="/index/Pri#primes">Index to Primes</a>, Primes that become a different prime under some mapping.

%t fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 4] || MemberQ[id, 5]) && PrimeQ[ FromDigits[ id /. {4 -> 5, 5 -> 4}] ]]; Select[ Prime@ Range@ 400, fQ]

%Y Cf. A171027, A175791, A180517 thru A180559, A175789, A180560, A180561.

%K base,nonn

%O 1,1

%A _Zak Seidov_ and _Robert G. Wilson v_, Sep 09 2010