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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
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
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.)