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Primes of the form Phi(k, 10), where Phi is the cyclotomic polynomial.
1

%I #8 Nov 11 2019 13:56:48

%S 11,101,9091,9901,909091,1111111111111111111,11111111111111111111111,

%T 99990001,999999000001,909090909090909091,900900900900990990990991,

%U 9999999900000001,909090909090909090909090909091,900900900900900900900900900900990990990990990990990990990991

%N Primes of the form Phi(k, 10), where Phi is the cyclotomic polynomial.

%H Robert Price, <a href="/A292014/b292014.txt">Table of n, a(n) for n = 1..19</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,10], {k, 0, 100}], PrimeQ[#] &]

%Y Cf. A138940.

%K nonn

%O 1,1

%A _Robert Price_, Sep 07 2017