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A105428
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Smallest prime dividing the composite near-repdigit number 133...33 consisting of a 1 followed by n 3's, where n=A105427.
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1
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7, 31, 67, 151, 23, 13, 7, 157, 163, 107, 17, 13, 7, 89, 170809, 31, 13, 7, 4363363, 251, 42169, 43, 13, 7, 641, 17, 6791, 109, 13, 7, 31, 29, 373, 261382937, 13, 7, 101921, 82647847, 443, 13, 7, 43, 1042402171, 71, 31, 13, 7, 1601, 425519761
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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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Transpose[FactorInteger[#]][[1, 1]]&/@DeleteCases[Table[ FromDigits[ PadRight[{1}, n, 3]], {n, 2, 60}], _?PrimeQ] (* Harvey P. Dale, Dec 10 2011 *)
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PROG
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(PARI) for(n=1, 100, m=10^n+(10^n-1)/3; if(!isprime(m), print1(factorint(m)[1, 1], " "))) (Alekseyev)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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