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A180543
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Primes that become a different prime under the mapping 3 <=> 7.
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1
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3, 7, 13, 17, 31, 37, 43, 47, 71, 73, 103, 107, 137, 139, 163, 167, 173, 179, 193, 197, 223, 227, 233, 277, 337, 347, 353, 379, 383, 439, 463, 467, 479, 613, 617, 643, 647, 739, 743, 757, 773, 787, 823, 827, 853, 857, 883, 887, 1093, 1097, 1213, 1217, 1321
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 3] || MemberQ[id, 7]) && PrimeQ[ FromDigits[ id /. {3 -> 7, 7 -> 3}] ]]; Select[ Prime@ Range@ 250, fQ]
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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