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 A285794 #10 Apr 27 2017 08:16:51
%S A285794 1,2,3,10,22,51,125,293,696,1657,3928,9330,22157,52601,124905,296578,
%T A285794 704191,1672062,3970178,9426875,22383417,53147701,126195160,299640813,
%U A285794 711474236,1689341342,4011212253,9524317645,22614766177,53697038226,127499523515
%N A285794 a(1)=1, a(2)=2, a(3)=3, a(n) = 3*a(n-3)+2*a(n-2)+a(n-1).
%H A285794 Harvey P. Dale, <a href="/A285794/b285794.txt">Table of n, a(n) for n = 1..1000</a>
%H A285794 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,2,3).
%F A285794 G.f.: x*(x^2-x-1)/(3*x^3+2*x^2+x-1).
%t A285794 LinearRecurrence[{1,2,3},{1,2,3},50]
%K A285794 nonn
%O A285794 1,2
%A A285794 _Harvey P. Dale_, Apr 26 2017