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A343589
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Smallest prime of the form n^k-(n-1) or 0 if no such prime exists.
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2
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3, 7, 13, 3121, 31, 43, 549755813881, 73, 991, 1321, 248821, 157, 2731, 211, 241, 34271896307617, 307, 6841, 13107199999999999999981, 421, 463, 141050039560662968926081, 331753, 601, 17551, 7625597484961, 757, 1816075630094014572464024421543167816955354437761
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OFFSET
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2,1
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COMMENTS
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All values up to n=70 have been found and proved to be primes. n=71 has k=3019 and gives a probable prime.
See A113516, which gives the k values and is the main entry for these primes, for more extensively researched information. - Peter Munn, Nov 20 2021
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LINKS
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Blake Branstool, Table of n, a(n) for n = 2..70
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EXAMPLE
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For n=2 and k=2, 2^2-(2-1)=3 thus a(2)=3. k is 2 as well for n=3,4.
For n=5 the first k to result in a prime is 5, 5^5-(5-1)=3121 thus a(5)=3121.
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PROG
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(PARI) a(n) = my(k=1, p); while (!isprime(p=n^k-(n-1)), k++); p; \\ Michel Marcus, Nov 17 2021
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CROSSREFS
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A113516 gives the k values.
Cf. A076846, A084741, A084745, A346154.
Sequence in context: A084741 A135623 A172291 * A089305 A112618 A058027
Adjacent sequences: A343586 A343587 A343588 * A343590 A343591 A343592
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KEYWORD
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nonn
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AUTHOR
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Blake Branstool, Apr 20 2021
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EXTENSIONS
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Name revised by Peter Munn, Nov 16 2021
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STATUS
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approved
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