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A180547
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Primes that become a different prime under the mapping 4 <=> 6.
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1
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41, 47, 61, 67, 347, 367, 401, 419, 431, 461, 463, 467, 491, 601, 619, 631, 641, 643, 647, 691, 947, 967, 1049, 1069, 1409, 1427, 1447, 1493, 1499, 1609, 1627, 1667, 1693, 1699, 1847, 1867, 2141, 2161, 2417, 2459, 2467, 2477, 2617, 2647, 2659, 2677, 3041
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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, 6]) && PrimeQ[ FromDigits[ id /. {4 -> 6, 6 -> 4}] ]]; Select[ Prime@ Range@ 440, fQ]
dpQ[n_]:=(DigitCount[n, 10, 4]>0 || DigitCount[n, 10, 6]>0)&&PrimeQ[ FromDigits[ IntegerDigits[n]/.{4->a, 6->b}/.{a->6, b->4}]]; Select[ Prime[ Range[500]], dpQ](* Harvey P. Dale, Feb 28 2022 *)
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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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