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A180550
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Primes that become a different prime under the mapping 4 <=> 9.
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1
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47, 97, 347, 397, 467, 491, 641, 691, 941, 967, 1433, 1447, 1451, 1487, 1933, 1951, 1987, 1997, 2243, 2293, 2417, 2543, 2593, 2741, 2791, 2917, 3407, 3467, 3907, 3967, 4001, 4007, 4013, 4091, 4093, 4127, 4133, 4157, 4243, 4283, 4337, 4391, 4423, 4597
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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, 4] || MemberQ[id, 9]) && PrimeQ[ FromDigits[ id /. {4 -> 9, 9 -> 4}] ]]; Select[ Prime@ Range@ 650, 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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