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%I #9 Jun 21 2016 19:23:41
%S 17,19,79,97,107,109,137,139,173,179,193,197,227,229,347,349,379,397,
%T 577,599,617,619,709,727,739,769,827,829,857,859,907,929,937,967,1279,
%U 1297,1427,1429,1487,1489,1579,1597,1607,1609,1667,1669,1709,1733,1747
%N Primes that become a different prime under the mapping 7 <=> 9.
%H John Cerkan, <a href="/A180559/b180559.txt">Table of n, a(n) for n = 1..10000</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, 7] || MemberQ[id, 9]) && PrimeQ[ FromDigits[ id /. {7 -> 9, 9 -> 7}] ]]; Select[ Prime@ Range@ 275, fQ]
%Y Cf. A171056, 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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