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 A231959 #10 Nov 22 2013 11:37:49
%S A231959 1,5,6,12,18,24,25,30,36,48,54,55,60,72,84,90,96,108,120,125,144,150,
%T A231959 162,168,180,192,216,240,252,270,275,276,288,300,306,324,330,336,342,
%U A231959 360,384,420,432,450,480,486,504,540,552,576,588,600,605,612,625
%N A231959 Numbers n dividing the Lucas sequence u(n) defined by u(i) = 3*u(i-1) - u(i-2) with initial conditions u(0)=0, u(1)=1.
%C A231959 All terms except 1 are divisible by either 5 or 6. The sequence contains every nonnegative integer power of 5. There are infinitely many multiples of 6 in the sequence and infinitely many consecutive integers in the sequence (for example, 5,6 or 24,25, or 54,55).
%H A231959 C. Smyth, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL13/Smyth/smyth2.html">The Terms in Lucas Sequences Divisible by their Indices</a>, Journal of Integer Sequences, Vol.13 (2010), Article 10.2.4.
%t A231959 nn = 1000; s = LinearRecurrence[{3, -1}, {1, 3}, nn]; t = {}; Do[If[Mod[s[[n]], n] == 0, AppendTo[t, n]], {n, nn}]; t (* _T. D. Noe_, Nov 22 2013 *)
%Y A231959 Cf. A000351 (powers of 5 (subsequence)).
%Y A231959 Cf. A001906 (Lucas sequence).
%K A231959 nonn
%O A231959 1,2
%A A231959 _Thomas M. Bridge_, Nov 15 2013