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A052430
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Numbers n such that sum of digits and product of digits are both prime.
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2
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2, 3, 5, 7, 12, 21, 113, 115, 131, 151, 311, 511, 1112, 1121, 1211, 2111, 11113, 11117, 11131, 11171, 11311, 11711, 13111, 17111, 31111, 71111, 111112, 111121, 111211, 112111, 121111, 211111, 1111115, 1111117, 1111151, 1111171, 1111511, 1111711
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OFFSET
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1,1
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COMMENTS
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One digit must be 2, 3, 5, or 7 and every other digit must be 1. If k is in the sequence, then so is every permutation of the digits of k. - Sean A. Irvine, Nov 08 2021
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LINKS
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EXAMPLE
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a(7)=115 because 1+1+5=7 which is prime and 1*1*5=5 which is prime
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MATHEMATICA
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okQ[n_]:=Module[{idn=IntegerDigits[n]}, PrimeQ[Total[idn]]&&PrimeQ[Times@@idn]]
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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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