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 A256153 #17 Mar 26 2015 04:44:43
%S A256153 5,31,11,71,311,2801,151,61,41,271,3221,22621,30941,3761,4931,88741,
%T A256153 2711,911,251,40841,245411,292561,346201,521,8641,4561,637421,732541,
%U A256153 837931,17351,601,1801,39451,22571,49831,101,4271,194681,191,401,2625641,579281
%N A256153 Primitive prime factors of the cyclotomic polynomial sequence Phi(5,k) in the order in which they occur.
%C A256153 Phi(5,k) = k^4 + k^3 + k^2 + k + 1.
%C A256153 All terms end with the digit 1.
%H A256153 Robert Price, <a href="/A256153/b256153.txt">Table of n, a(n) for n = 1..1191</a>
%t A256153 prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[5, k]], prim]], {k, 1000}]; prim
%o A256153 (PARI) lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(5,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 A256153 Cf. A005529, A248874, A256144, A256145, A256146, A256148.
%K A256153 nonn
%O A256153 1,1
%A A256153 _Robert Price_, Mar 16 2015