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 A231114 #40 Feb 08 2020 08:17:11
%S A231114 1,3,5,9,15,25,27,45,75,81,125,135,171,225,243,375,405,435,465,513,
%T A231114 625,675,729,855,1125,1215,1305,1395,1539,1875,2025,2175,2187,2325,
%U A231114 2565,3125,3249,3375,3645,3725,3915,4005,4185,4275,4617,5625,6075,6327,6525,6561
%N A231114 Numbers k dividing u(k), where the Lucas sequence is defined u(i) = u(i-1) - 4*u(i-2) with initial conditions u(0)=0, u(1)=1.
%C A231114 Every term (except leading term) is divisible by at least one of 3 or 5.
%C A231114 Furthermore, this sequence contains 3^i*5^j for all i, j >= 0, that is, A003593 is a subsequence.
%H A231114 Amiram Eldar, <a href="/A231114/b231114.txt">Table of n, a(n) for n = 1..1000</a>
%H A231114 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.
%H A231114 Wikipedia, <a href="http://en.wikipedia.org/wiki/Lucas_sequence">Lucas sequence</a>
%e A231114 The sequence u(i) begins 0, 1, 1, -3, -7, 5, 33. Only for k = 1, 3, 5 does k divides u(k).
%t A231114 nn = 10000; s = LinearRecurrence[{1, -4}, {1, 1}, nn]; t = {}; Do[If[Mod[s[[n]], n] == 0, AppendTo[t, n]], {n, nn}]; t (* _T. D. Noe_, Nov 06 2013 *)
%Y A231114 Cf. A003593 (subsequence), A106853 (Lucas sequence).
%K A231114 nonn
%O A231114 1,2
%A A231114 _Thomas M. Bridge_, Nov 06 2013