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A128005
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Numbers n such that (40^n - 1)/39 is prime.
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17
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OFFSET
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1,1
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COMMENTS
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No other terms for n < 100000. - Robert Price, Jan 27 2012
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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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Table of n, a(n) for n=1..9.
H. Lifchitz, Mersenne and Fermat primes field
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MATHEMATICA
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Select[Prime[Range[100]], PrimeQ[(40^#-1)/39]&]
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CROSSREFS
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Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035, A127995, A127996, A127997, A127998, A127999, A128000, A098438, A128002, A128003, A128004.
Sequence in context: A097052 A102937 A045358 * A045359 A042809 A108413
Adjacent sequences: A128002 A128003 A128004 * A128006 A128007 A128008
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KEYWORD
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hard,more,nonn
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AUTHOR
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Alexander Adamchuk, Feb 11 2007
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
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STATUS
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approved
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