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A217410
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Numbers of the form 3^r*7^s whose decimal representations are such that each digit 0-9 appears a prime number of times.
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13
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OFFSET
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1,1
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COMMENTS
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See the formula section for more data, and the others in cross-reference for similar sequences and motivation.
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LINKS
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FORMULA
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EXAMPLE
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A217411(1)=37 and A217412(1)=10, so this sequence's first term is (3^37)*(7^10). It is the smallest number with exactly 3 and 7 as its prime factors to have decimal representation with each digit 0-9 counted a prime number of times. The digits 0, 2, 3, 5, 6 and 9 occur two times each; 1, 4 and 8 occur three times each; and 7 occurs five times.
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CROSSREFS
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Cf. A216854, A217411, A217412, A217404, A217407, A217410, A217416, A217419, A217422, A217425, A217428, A217431.
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KEYWORD
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nonn,base,less
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AUTHOR
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STATUS
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approved
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