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 A034923 Numbers k such that 43^k - 42 is prime. 0
 4, 6, 42, 64, 65, 1017, 3390, 3894, 8904, 12976 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Related to hyperperfect numbers of a certain form. k = 1017 produces a 1662-digit number which is only a probable prime. Any additional terms are greater than 1500. The next terms are > 3000. - Vincenzo Librandi, Sep 27 2012 LINKS Table of n, a(n) for n=1..10. J. S. McCranie, A study of hyperperfect numbers, J. Int. Seqs. Vol. 3 (2000) #P00.1.3. MATHEMATICA Select[Range[1500], PrimeQ[43^# - 42] &] (* Vincenzo Librandi, Sep 27 2012 *) PROG (PARI) for(n=2, 1500, if(isprime(43^n-42), print1(n, ", "))) CROSSREFS Sequence in context: A319672 A355233 A145387 * A013022 A012908 A306842 Adjacent sequences: A034920 A034921 A034922 * A034924 A034925 A034926 KEYWORD nonn,more AUTHOR Jud McCranie EXTENSIONS a(6) from Rick L. Shepherd, Jun 21 2002 a(7)-a(8) from Michael S. Branicky, Aug 15 2021 a(9)-a(10) from Michael S. Branicky, Mar 28 2023 STATUS approved

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Last modified September 29 06:38 EDT 2023. Contains 365757 sequences. (Running on oeis4.)