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 A273814 Numbers k such that (12^k - 7^k)/5 is prime. 1
 2, 3, 7, 13, 47, 89, 139, 523, 1051 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are prime. The corresponding primes are 19, 277, 7001653, 21379263273733, 105329145253605843602014309589572596276217801876213, ... LINKS MAPLE A273814:=n->`if`(isprime((12^n - 7^n)/5), n, NULL): seq(A273814(n), n=1..10^3); # Wesley Ivan Hurt, Jun 01 2016 MATHEMATICA Select[Range[1, 10000], PrimeQ[(12^# - 7^#)/5] &] PROG (PARI) for(n=1, 10000, if(isprime((12^n - 7^n)/5), print1(n, ", "))) CROSSREFS Cf. A004064, A062578, A128348. Sequence in context: A206579 A166945 A257393 * A085872 A070858 A061067 Adjacent sequences:  A273811 A273812 A273813 * A273815 A273816 A273817 KEYWORD nonn,more,hard AUTHOR Tim Johannes Ohrtmann, May 31 2016 STATUS approved

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Last modified June 24 14:24 EDT 2021. Contains 345417 sequences. (Running on oeis4.)