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 A068219 #12 Sep 21 2018 22:19:12
%S A068219 3,3,9,3,15,9,21,6,27,15,33,9,39,21,45,12,51,27,57,15,63,33,69,18,75,
%T A068219 39,81,21,87,45,93,24,99,51,105,27,111,57,117,30,123,63,129,33,135,69,
%U A068219 141,36,147,75,153,39,159,81,165,42,171,87,177,45,183,93,189,48,195,99
%N A068219 Denominators of coefficients in log(1+x)*(1+x)^(1/3) power series.
%C A068219 log(1+x)*(1+x)^(1/3) = (-4)*sum(k=>1,(-x)^k/(3k))
%H A068219 G. C. Greubel, <a href="/A068219/b068219.txt">Table of n, a(n) for n = 1..10000</a>
%F A068219 a(n) = 3*n if n==1 or 3 (mod 4), a(n) = 3*n/2 if n==2 (mod 4), a(n) = 3*n/4 if n==0 (mod 4).
%F A068219 a(n) = 3*A060819(n). - _Mitch Harris_, Jun 29 2005
%t A068219 fn[n_]:=Module[{m=Mod[n,4]},Which[OddQ[m],3n,m==2,3 n/2,True,3 n/4]]; Array[fn,70] (* _Harvey P. Dale_, Sep 18 2012 *)
%K A068219 easy,frac,nonn
%O A068219 1,1
%A A068219 _Benoit Cloitre_, Mar 30 2002