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 A256146 #11 Mar 24 2015 17:53:06
%S A256146 7,127,1093,43,19531,55987,29,4733,337,547,239,4649,45319,659,4943,
%T A256146 5229043,8108731,1743463,113,25646167,449,80207,701,70841,71,32719,
%U A256146 631,3319,16968421,5336717,28771,321272407,368089,4422461,88009573,93997,917087137,122921
%N A256146 Primitive prime factors of the cyclotomic polynomial sequence Phi(7,k) in the order in which they occur.
%C A256146 Phi(7,k) = k^6 + k^5 + k^4 + k^3 + k^2 + k + 1.
%H A256146 Robert Price, <a href="/A256146/b256146.txt">Table of n, a(n) for n = 1..1511</a>
%t A256146 prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[7, k]], prim]], {k, 1000}]; prim
%o A256146 (PARI) lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(7,n))[,1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]),,8););););} \\ _Michel Marcus_, Mar 20 2015
%Y A256146 Cf. A005529, A248874, A256144, A256145.
%K A256146 nonn
%O A256146 1,1
%A A256146 _Robert Price_, Mar 16 2015