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User: Blake Branstool

Blake Branstool has authored 1 sequences.

A343589 Smallest prime of the form n^k-(n-1) or 0 if no such prime exists.

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

Offset: 2

Blake Branstool, Apr 20 2021

nonn

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

			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.

Blake Branstool, Table of n, a(n) for n = 2..70

A113516 gives the k values.

Cf. A076846, A084741, A084745, A346154.

a(n) = my(k=1, p); while (!isprime(p=n^k-(n-1)), k++); p; \\ Michel Marcus, Nov 17 2021

Name revised by Peter Munn, Nov 16 2021

cp's OEIS Frontend

User: Blake Branstool

A343589 Smallest prime of the form n^k-(n-1) or 0 if no such prime exists.

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