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A131306
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Smallest prime ending with exactly n identical digits.
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1
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2, 11, 1777, 23333, 199999, 2999999, 19999999, 577777777, 1777777777, 23333333333, 311111111111, 2111111111111, 17777777777777, 499999999999999, 1333333333333333, 23333333333333333
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OFFSET
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1,1
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COMMENTS
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By Dirichlet's theorem, there is a prime for each n. For the n in A004023, the smallest prime consists of all ones. - T. D. Noe, Oct 01 2007
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LINKS
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EXAMPLE
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a(4)=23333 because 23333 is the smallest prime ending with exactly 4 identical digits.
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MATHEMATICA
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sp[n_]:=Module[{k=1}, While[!PrimeQ[k*10^IntegerLength[n]+n], k++]; k*10^IntegerLength[n]+n]; Join[{2, 11}, Table[Min[sp/@FromDigits/@ Table[PadRight[{}, i, n], {n, {1, 3, 7, 9}}]], {i, 3, 20}]] (* Harvey P. Dale, Aug 28 2016 *)
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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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