A291998 - OEIS

%I #9 Nov 11 2019 13:48:32

%S 521,31,601,19531,12207031,390001,305175781,234750601,

%T 60081451169922001,152587500001,10910444855403996246103496881,

%U 59509429687890001,11293772630057337854244300009061892827351888021,9080418348371887359375390001,5465713352000770660547109750601

%N Primes of the form Phi(k, -5), where Phi is the cyclotomic polynomial.

%H Robert Price, <a href="/A291998/b291998.txt">Table of n, a(n) for n = 1..31</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,-5], {k, 0, 100}], PrimeQ[#] &]

%Y Cf. A138925.

%K nonn

%O 1,1

%A _Robert Price_, Sep 07 2017