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 A265485 Numbers n such that 49^n - 7^n - 1 is prime. 1
 1, 2, 12, 14, 110, 2574, 10964, 24257, 44364 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For n = 1, 2, 12, 14 the corresponding primes are 41, 2351, 191581231366725127199, 459986536544061737903951. a(10) > 10^5. - Robert Price, Dec 25 2019 LINKS Table of n, a(n) for n=1..9. EXAMPLE 2 is in the sequence because 49^2 - 7^2 - 1 = 2351 is prime. MATHEMATICA Select[Range[2000], PrimeQ[49^# - 7^# - 1] &] PROG (Magma) [n: n in [0..1000] | IsPrime(49^n - 7^n - 1)]; (PARI) for(n=1, 1e3, if(ispseudoprime(49^n - 7^n - 1), print1(n, ", "))) \\ Altug Alkan, Dec 12 2015 CROSSREFS Cf. similar sequences listed in A265481. Sequence in context: A260899 A108969 A269130 * A166745 A352504 A262094 Adjacent sequences: A265482 A265483 A265484 * A265486 A265487 A265488 KEYWORD nonn,more AUTHOR Vincenzo Librandi, Dec 12 2015 EXTENSIONS a(6) from Ray Chandler, Sep 25 2019 a(7)-a(9) from Robert Price, Dec 25 2019 STATUS approved

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Last modified June 23 05:53 EDT 2024. Contains 373629 sequences. (Running on oeis4.)