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 A100598 Numbers k such that (prime(k)-1)! + prime(k)^8 is prime. 2
 1, 2, 4, 5, 8, 10 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS k = {1, 2, 4, 5, 8, 10} yields primes p(k) = {2, 3, 7, 11, 19, 29}. There are no more such k up to k=100. Computed in collaboration with Ray Chandler. a(7) > 600. - Jinyuan Wang, Apr 10 2020 a(7) > 900. - Tyler NeSmith, May 05 2021 LINKS EXAMPLE a(1) = 1 because (prime(1)-1)! + prime(1)^8 = (2-1)! + 2^8 = 257 is the smallest prime of that form. a(5) = 8 because (prime(8)-1)! + prime(8)^8 = (19-1)! + 19^8 = 304888344611713861001750412961 is the 5th smallest prime of that form. MATHEMATICA lst={}; Do[p=Prime[n]; If[PrimeQ[(p-1)!+p^8], AppendTo[lst, n]], {n, 10^2}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 08 2008 *) PROG (PARI) is(k) = ispseudoprime((prime(k)-1)! + prime(k)^8); \\ Jinyuan Wang, Apr 10 2020 CROSSREFS Cf. A100595, A100599, A100858. Sequence in context: A277010 A101394 A095031 * A191535 A079537 A094591 Adjacent sequences:  A100595 A100596 A100597 * A100599 A100600 A100601 KEYWORD nonn,hard,more,less AUTHOR Jonathan Vos Post, Nov 30 2004 EXTENSIONS Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Jun 08 2007 STATUS approved

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Last modified September 24 08:31 EDT 2021. Contains 347623 sequences. (Running on oeis4.)