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A242797
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Numbers n such that (45^n - 1)/44 is prime.
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5
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OFFSET
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1,1
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COMMENTS
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a(7) > 10^5.
Numbers corresponding to a(4)-a(6) are probable primes.
All terms are prime.
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LINKS
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Table of n, a(n) for n=1..7.
Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
Henri Lifchitz, Mersenne and Fermat primes field
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MAPLE
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A242797:=n->`if`(isprime((45^n - 1)/44), n, NULL); seq(A242797(n), n=1..100000); # Wesley Ivan Hurt, Apr 12 2014
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MATHEMATICA
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Select[Prime[Range[100000]], PrimeQ[(45^# - 1)/44] &]
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PROG
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(PARI) is(n)=ispseudoprime((45^n-1)/44) \\ Charles R Greathouse IV, Feb 20 2017
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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, A098438, A128002, A128003, A128004, A128005, A240765.
Sequence in context: A024848 A240136 A072581 * A142072 A221594 A288144
Adjacent sequences: A242794 A242795 A242796 * A242798 A242799 A242800
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KEYWORD
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hard,more,nonn
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AUTHOR
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Robert Price, May 22 2014
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EXTENSIONS
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a(7)=216551 corresponds to a probable prime discovered by Paul Bourdelais, Aug 04 2020
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STATUS
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approved
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