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 A152896 #6 Jun 13 2015 00:52:45
%S A152896 0,3,15,55,183,588,1865,5887,18550,58414,183904,578936,1822459,
%T A152896 5736946,18059358,56849069,178955165,563332829,1773314909,5582216334,
%U A152896 17572253459,55315679765,174128175040,548137914348,1725482812062
%N A152896 a=b=c=0;c(n)=c+n+a;b(n)=b+n+c;a(n)=a+n+b.
%H A152896 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (6, -12, 11, -5, 1).
%F A152896 G.f.: x^2(3-3x+x^2)/((1-x)^2*(1-4x+3x^2-x^3)). a(n)=6*a(n-1)-12*a(n-2)+11*a(n-3)-5*a(n-4)+a(n-5). [From _R. J. Mathar_, Dec 15 2008]
%t A152896 lst={};a=b=c=0;Do[c+=n+a;b+=n+c;a+=n+b;AppendTo[lst,a],{n,0,2*4!}];lst
%t A152896 LinearRecurrence[{6,-12,11,-5,1},{0,3,15,55,183},30] (* _Harvey P. Dale_, Dec 11 2014 *)
%Y A152896 Cf. A152891, A152895
%K A152896 nonn
%O A152896 1,2
%A A152896 _Vladimir Joseph Stephan Orlovsky_, Dec 14 2008