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A093944
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Primes of the form 9*10^k + 7*R_k, where R_k is the repunit (A002275) of length k.
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1
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OFFSET
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1,1
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COMMENTS
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The next term has 204 digits. - Harvey P. Dale, May 22 2014
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LINKS
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Table of n, a(n) for n=1..6.
Makoto Kamada, Prime numbers of the form 977...77.
Index entries for primes involving repunits
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MATHEMATICA
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Select[Table[FromDigits[PadRight[{9}, n, 7]], {n, 250}], PrimeQ] (* Harvey P. Dale, May 22 2014 *)
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CROSSREFS
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Cf. A002275, A056727 (corresponding k).
Sequence in context: A262925 A093297 A068852 * A127748 A127828 A186075
Adjacent sequences: A093941 A093942 A093943 * A093945 A093946 A093947
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KEYWORD
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nonn
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AUTHOR
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Rick L. Shepherd, Apr 17 2004
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STATUS
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approved
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