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Primes of the form Phi(k, -7), where Phi is the cyclotomic polynomial.
1

%I #9 Nov 11 2019 13:48:17

%S 43,117307,2801,6568801,29078814248401,3421093417510114543,

%T 79787519018560501,16148168401,1628413557556843,13564461457,

%U 402488219476647465854701,13841169553,11898664849,655417289594537954307682339857743931943,33232924804801

%N Primes of the form Phi(k, -7), where Phi is the cyclotomic polynomial.

%H Robert Price, <a href="/A291993/b291993.txt">Table of n, a(n) for n = 1..23</a>

%H Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/papers/cyclotomic.html">Cyclotomic polynomials and prime numbers</a>

%H <a href="/index/Cy#CyclotomicPolynomialsValuesAtX">Index entries for cyclotomic polynomials,values at X</a>

%t Select[Table[Cyclotomic[k,-7], {k, 0, 100}], PrimeQ[#] &]

%Y Cf. A138923.

%K nonn

%O 1,1

%A _Robert Price_, Sep 07 2017