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 A119852 #9 Jul 31 2015 18:23:07
%S A119852 0,0,0,1,6,27,106,387,1350,4566,15102,49113,157622,500520,1575558,
%T A119852 4923536,15290784,47235771,145246224,444814533,1357368786,4128880561,
%U A119852 12523521786,37888119522,114358226428,344437708131,1035409733820
%N A119852 Number of ternary words with exactly one 012.
%C A119852 Except for the initial three zeros, convolution of A076264 with itself. Column 1 of A119851.
%H A119852 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (6, -9, -2, 6, 0, -1).
%F A119852 G.f.=z^3/(1-3z+z^2)^2.
%F A119852 a(0)=0, a(1)=0, a(2)=0, a(3)=1, a(4)=6, a(5)=27, a(n)=6*a(n-1)- 9*a(n-2)- 2*a(n-3)+6*a(n-4)-a(n-6). - _Harvey P. Dale_, Apr 28 2014
%e A119852 a(4)=6 because we have 0012, 0120, 0121, 0122, 1012 and 2012.
%p A119852 G:=z^3/(1-3*z+z^3)^2: Gser:=series(G,z=0,34): seq(coeff(Gser,z,n),n=0..30);
%t A119852 CoefficientList[Series[z^3/(1-3z+z^3)^2,{z,0,30}],z] (* or *) LinearRecurrence[ {6,-9,-2,6,0,-1},{0,0,0,1,6,27},30] (* _Harvey P. Dale_, Apr 28 2014 *)
%Y A119852 Cf. A076264, A119851.
%K A119852 nonn
%O A119852 0,5
%A A119852 _Emeric Deutsch_, May 26 2006