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%I #11 Oct 30 2023 17:12:01
%S 47,97,347,397,467,491,641,691,941,967,1433,1447,1451,1487,1933,1951,
%T 1987,1997,2243,2293,2417,2543,2593,2741,2791,2917,3407,3467,3907,
%U 3967,4001,4007,4013,4091,4093,4127,4133,4157,4243,4283,4337,4391,4423,4597
%N Primes that become a different prime under the mapping 4 <=> 9.
%H Robert Price, <a href="/A180550/b180550.txt">Table of n, a(n) for n = 1..1559</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, 9]) && PrimeQ[ FromDigits[ id /. {4 -> 9, 9 -> 4}] ]]; Select[ Prime@ Range@ 650, fQ]
%Y Cf. A171053, A175791, A180517 thru A180559, A175789, A180560, A180561.
%K base,nonn
%O 1,1
%A _Zak Seidov_ and _Robert G. Wilson v_, Sep 09 2010
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