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 A128075 Numbers n such that (3^n + 19^n)/22 is prime. 12
 3, 61, 71, 109, 9497, 36007, 50461, 66919 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. a(9) > 10^5. - Robert Price, Jul 21 2013 LINKS MATHEMATICA k=19; Do[ p=Prime[n]; f=(3^p+k^p)/(k+3); If[ PrimeQ[f], Print[p]], {n, 1, 9592} ] PROG (PARI) is(n)=isprime((3^n+19^n)/22) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A007658 = numbers n such that (3^n + 1)/4 is prime. Cf. A057469 = numbers n such that (3^n + 2^n)/5 is prime. Cf. A122853 = numbers n such that (3^n + 5^n)/8 is prime. Cf. A128066, A128067, A128068, A128069, A128070, A128071, A128072, A128073, A128074. Cf. A059801 = numbers n such that 4^n - 3^n is prime. Cf. A121877 = numbers n such that (5^n - 3^n)/2 is a prime. Cf. A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032. Sequence in context: A093883 A203518 A297562 * A106883 A037209 A181505 Adjacent sequences:  A128072 A128073 A128074 * A128076 A128077 A128078 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 14 2007 EXTENSIONS a(5)-a(8) from Robert Price, Jul 21 2013 STATUS approved

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Last modified June 20 09:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)