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 A093379 #8 May 10 2019 15:11:19
%S A093379 0,1,2,5,12,31,82,225,632,1811,5262,15445,45652,135591,404042,1206665,
%T A093379 3609072,10805371,32372422,97029885,290914892,872395151,2616486402,
%U A093379 7848061105,23541387112,70618568931,211844521982,635511196325
%N A093379 Expansion of x(1-2x-2x^2)/((1+x)(1-2x)(1-3x)).
%C A093379 Binomial transform is A085280, with leading zero.
%H A093379 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-1,-6).
%F A093379 a(n)=3^n/12-(-1)^n/12+2^n/3-0^n/3;
%F A093379 a(n)=4a(n-1)-a(n-2)-6a(n-3).
%F A093379 a(n)=A015518(n)/3+A000079(n)/3-0^n/3.
%t A093379 CoefficientList[Series[x (1-2x-2x^2)/((1+x)(1-2x)(1-3x)),{x,0,30}],x] (* or *) LinearRecurrence[{4,-1,-6},{0,1,2,5},40] (* _Harvey P. Dale_, May 10 2019 *)
%Y A093379 Cf. A087432.
%K A093379 easy,nonn
%O A093379 0,3
%A A093379 _Paul Barry_, Apr 28 2004