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 A108105 #14 Oct 03 2016 11:45:09
%S A108105 1,1,1,1,1,2,2,2,2,2,4,4,4,4,4,8,8,8,8,8,16,16,16,16,16,32,32,32,32,
%T A108105 32,64,64,64,64,64,128,128,128,128,128,256,256,256,256,256,512,512,
%U A108105 512,512,512,1024
%N A108105 2^floor(n/5).
%H A108105 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,2).
%F A108105 G.f.: (1+x+x^2+x^3+x^4)/(1-2*x^5).
%t A108105 s[1] = {2}; s[2] = {3}; s[3] = {4}; s[4] = {5}; s[5] = {1, 6}; s[6] = {2}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] a0 = Table[Length[p[i]], {i, 0, 50}]
%o A108105 (PARI) a(n)=2^(n\5) \\ _Charles R Greathouse IV_, Oct 03 2016
%K A108105 nonn,easy
%O A108105 0,6
%A A108105 _Roger L. Bagula_, Jun 03 2005