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Primes of the form Phi(8,n!), where Phi is the cyclotomic polynomial.
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%I #20 Nov 17 2015 09:21:59

%S 2,17,1297,331777,1503561738404723998944447273369600000001

%N Primes of the form Phi(8,n!), where Phi is the cyclotomic polynomial.

%C a(6) is 730 digits.

%H OEIS Wiki, <a href="https://oeis.org/wiki/Cyclotomic Polynomials at x=n, n! and sigma(n)">Cyclotomic Polynomials at x=n, n! and sigma(n)</a>

%t Select[Table[Cyclotomic[8, n!], {n, 0, 200}], PrimeQ]

%o (PARI) for(n=1, 500, if(isprime(k=polcyclo(8, n!)), print1(k", "))) \\ _Altug Alkan_, Nov 16 2015

%Y Cf. A123865, A200906, A259264, A259265, A260478.

%K nonn

%O 1,1

%A _Robert Price_, Aug 28 2015