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 A124378 #4 Mar 20 2013 18:01:53
%S A124378 5,8,12,13,17,21,28,33,37,53,57,61,69,73,77,87,89,92,93,97,109,113,
%T A124378 133,137,141,149,157,164,172,173,177,188,193,197,203,213,217,233,237,
%U A124378 253,257,268,269,277,287,293,301,303,309,313,317,329,332,337,353,373,381
%N A124378 Primitive elements of A064362.
%C A124378 Numbers n such that no Lucas number is a multiple of n, which are not divisible by any smaller number with that property.
%H A124378 T. D. Noe, <a href="/A124378/b124378.txt">Table of n, a(n) for n = 1..1000</a>
%t A124378 test[n_] := Module[{a, b, t}, {a, b} = {2, 1}; While[t = b; b = Mod[a + b, n]; a = t; ! (b == 0 || {a, b} == {2, 1})]; b == 0]; t = {}; n = 0; While[Length[t] < 1000, n++; If[! MemberQ[Mod[n, t], 0] && ! test[n], AppendTo[t, n]]]; t (* _T. D. Noe_, Mar 20 2013 *)
%Y A124378 Cf. A064362, A065156.
%K A124378 nonn
%O A124378 1,1
%A A124378 _Franklin T. Adams-Watters_, Oct 28 2006