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 A283653 Numbers k such that 3^k + (-2)^k is prime. 4
 0, 2, 3, 4, 5, 17, 29, 31, 53, 59, 101, 277, 647, 1061, 2381, 2833, 3613, 3853, 3929, 5297, 7417, 90217, 122219, 173191, 256199, 336353, 485977, 591827, 1059503 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers j such that both 3^j + (-2)^j and 3^j + (-4)^j are primes: 0, 3, 4, 17, 59, ... See Michael Somos comment in A082101. Probably this is just A057468 with 0,2,4 added, because we already know that if another even number belong to this sequence it must be greater than log_3(10^16000000) = about 3.3*10^7. This is because 3^n+2^n can be a prime with n>0 only if n is a power of 2. - Giovanni Resta, Mar 12 2017 LINKS EXAMPLE 4 is in this sequence because 3^4 + (-2)^4 = 97 is prime. MATHEMATICA Select[Range[0, 10000], PrimeQ[3^# + (-2)^#] &] (* G. C. Greubel, Jul 29 2018 *) PROG (MAGMA) [n: n in [0..1000] | IsPrime(3^n+(-2)^n)]; (PARI) is(n)=isprime(3^n+(-2)^n) \\ Charles R Greathouse IV, Mar 16 2017 CROSSREFS Cf. A174326. Subsequence of A087451. Supersequence of A057468. Cf. A082101. Sequence in context: A240906 A117885 A030574 * A162657 A305794 A317944 Adjacent sequences:  A283650 A283651 A283652 * A283654 A283655 A283656 KEYWORD nonn,more AUTHOR Juri-Stepan Gerasimov, Mar 12 2017 STATUS approved

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Last modified October 20 17:33 EDT 2018. Contains 316393 sequences. (Running on oeis4.)