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 A292014 #8 Nov 11 2019 13:56:48
%S A292014 11,101,9091,9901,909091,1111111111111111111,11111111111111111111111,
%T A292014 99990001,999999000001,909090909090909091,900900900900990990990991,
%U A292014 9999999900000001,909090909090909090909090909091,900900900900900900900900900900990990990990990990990990990991
%N A292014 Primes of the form Phi(k, 10), where Phi is the cyclotomic polynomial.
%H A292014 Robert Price, <a href="/A292014/b292014.txt">Table of n, a(n) for n = 1..19</a>
%H A292014 Yves Gallot, <a href="http://yves.gallot.pagesperso-orange.fr/papers/cyclotomic.html">Cyclotomic polynomials and prime numbers</a>
%H A292014 <a href="/index/Cy#CyclotomicPolynomialsValuesAtX">Index entries for cyclotomic polynomials,values at X</a>
%t A292014 Select[Table[Cyclotomic[k,10], {k, 0, 100}], PrimeQ[#] &]
%Y A292014 Cf. A138940.
%K A292014 nonn
%O A292014 1,1
%A A292014 _Robert Price_, Sep 07 2017