This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A291913 #9 Nov 11 2019 13:47:46
%S A291913 13421,1623931,1772893,212601841,3421169496361,195019441,
%T A291913 50544702849929377,3138426605161,6115909044841454629,
%U A291913 9768997162071483134919121,5559917315850179173,46329453543600481,9842332430037465033595921
%N A291913 Primes of the form Phi(k, -11), where Phi is the cyclotomic polynomial.
%H A291913 Robert Price, <a href="/A291913/b291913.txt">Table of n, a(n) for n = 1..20</a>
%H A291913 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/papers/cyclotomic.html">Cyclotomic polynomials and prime numbers</a>
%H A291913 <a href="/index/Cy#CyclotomicPolynomialsValuesAtX">Index entries for cyclotomic polynomials,values at X</a>
%t A291913 Select[Table[Cyclotomic[k,-11], {k, 0, 100}], PrimeQ[#] &]
%Y A291913 Cf. A138919.
%K A291913 nonn
%O A291913 1,1
%A A291913 _Robert Price_, Sep 05 2017