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Search: id:A127995
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| A127995 |
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Numbers n such that (20^n - 1)/19 is prime. |
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+0
13
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OFFSET
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1,1
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REFERENCES
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H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
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LINKS
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H. Lifchitz, Mersenne and Fermat primes field
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MATHEMATICA
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Select[Prime[Range[100]], PrimeQ[(20^#-1)/19]&]
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CROSSREFS
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Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035. Cf. A127996, A127997, A127998, A127999, A128000, A098438, A128002, A128003, A128004, A128005.
Sequence in context: A036448 A128346 A128031 this_sequence A119141 A117769 A030377
Adjacent sequences: A127992 A127993 A127994 this_sequence A127996 A127997 A127998
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KEYWORD
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bref,hard,more,nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 11 2007
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EXTENSIONS
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One more term from Ryan Propper (rpropper(AT)stanford.edu), Mar 29 2007
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