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 A160773 Numbers k such that 3^k + 5^k + 7^k is prime. 4
 0, 2, 10, 14, 24, 26, 126, 514, 522, 1658, 13758, 77194 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Note that k must be even. REFERENCES Joao Carlos Leandro da Silva, The Rainbow of Primes, Freund Publishing House, Tel Aviv, 2009. LINKS EXAMPLE For k=2 we obtain f(2) = 3^2 + 5^2 + 7^2 = 83 which is a prime. MAPLE A160773:=n->`if`(isprime(3^n+5^n+7^n), n, NULL): seq(A160773(n), n=0..1000); # Wesley Ivan Hurt, Sep 19 2014 MATHEMATICA Select[Range[0, 1000], PrimeQ[3^# + 5^# + 7^#] &] (* Wesley Ivan Hurt, Sep 19 2014 *) PROG (PARI) isok(n) = isprime(3^n + 5^n + 7^n) \\ Michel Marcus, Jul 25 2013 (Python) def A160773_gen(): # generator of terms     p3, p5, p7 = [1]*3     for k in count(0):         if isprime(p3+p5+p7): yield k         p3 *= 3         p5 *= 5         p7 *= 7 A160773_list = list(islice(A160773_gen(), 6)) # Chai Wah Wu, Dec 27 2021 CROSSREFS Sequence in context: A091999 A230624 A290143 * A217191 A190043 A217681 Adjacent sequences:  A160770 A160771 A160772 * A160774 A160775 A160776 KEYWORD nice,nonn,more AUTHOR Joao Carlos Leandro da Silva (zxawyh66(AT)yahoo.com), May 26 2009, Jun 01 2009 EXTENSIONS Zero added by Zak Seidov, Oct 10 2009 STATUS approved

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Last modified August 18 02:34 EDT 2022. Contains 356204 sequences. (Running on oeis4.)