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 A115054 #13 Jun 13 2015 00:52:02
%S A115054 4,16,-8,-36,72,-36,-63,126,-63,-90,180,-90,-117,234,-117,-144,288,
%T A115054 -144,-171,342,-171,-198,396,-198,-225,450,-225,-252,504,-252,-279,
%U A115054 558,-279,-306,612,-306,-333,666,-333,-360,720,-360,-387,774,-387,-414,828,-414,-441,882,-441,-468,936,-468,-495,990,-495
%N A115054 G.f.: (x^3+6*x+2)^2/(x^2+x+1)^2.
%C A115054 q=3 coefficient expansion of hierarchical lattice renormalization polynomial.
%C A115054 Auto-convolution of the sequence 2,4,-6,3,3,-6,3,3,.. (period length 3). [From _R. J. Mathar_, Mar 09 2009]
%D A115054 Peitgen and Richter, The Beauty of Fractals, Springer-Verlag, New York, 1986, page 146
%H A115054 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (-2,-3,-2,-1).
%F A115054 a(n) = 18*A131713(n)-27*(-1)^n*A099254(n), n>2. [From _R. J. Mathar_, Mar 09 2009]
%p A115054 G:=(x^3+6*x+2)^2/(x^2+x+1)^2: Gser:=series(G,x=0,55): seq(coeff(Gser,x,n),n=0..50);
%t A115054 q=3 b = 9*Flatten[{{4/9}, Abs[Table[Coefficient[ Series[((x^3 + 3*(q - 1)*x + (q - 1)*(q - 2))/(3*x^2 + 3*( q - 2)*x + q^2 - 3*q + 3))^2, {x, 0, 30}], x^n], {n, 1, 30}]]}]
%K A115054 sign,easy
%O A115054 0,1
%A A115054 _Roger L. Bagula_, Feb 28 2006
%E A115054 Edited by _N. J. A. Sloane_, Apr 16 2006