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A036944
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Smallest n-digit prime containing only the digits 4 and 7, or 0 if no such prime exists.
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2
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7, 47, 0, 4447, 44777, 0, 4444747, 44447747, 0, 4444444447, 44444444747, 0, 4444444447777, 44444447447447, 0, 4444444447447777, 44444444444444477, 0, 4444444444444444777, 44444444444444444447, 0, 4444444444444444444747, 44444444444444444444477, 0
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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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Flatten[Table[Select[FromDigits/@Tuples[{4, 7}, n], PrimeQ, 1], {n, 22}]/.{}->{0}] (* Harvey P. Dale, Jun 28 2012 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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