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 A167704 #10 Jun 21 2016 02:40:59
%S A167704 1,0,2,1,3,3,6,7,12,16,25,35,53,76,113,164,242,353,519,759,1114,1631,
%T A167704 2392,3504,5137,7527,11033,16168,23697,34728,50898,74593,109323,
%U A167704 160219,234814,344135,504356,739168,1083305,1587659,2326829,3410132,4997793,7324620
%N A167704 a(0)=1, a(1)=0, a(2)=2, a(3)=1, a(n)=a(n-2)+a(n-3)+a(n-4) for n>3.
%C A167704 Diagonal sums of triangle in A122950.
%H A167704 G. C. Greubel, <a href="/A167704/b167704.txt">Table of n, a(n) for n = 0..1000</a>
%H A167704 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 1, 1, 1).
%F A167704 G.f.: (1-x^3)/(1-x^2-x^3-x^4).
%F A167704 a(n) = a(n-2) + a(n-3) + a(n-4). - _G. C. Greubel_, Jun 20 2016
%t A167704 LinearRecurrence[{0,1,1,1},{1,0,2,1},50] (* _Harvey P. Dale_, Aug 09 2015 *)
%K A167704 nonn
%O A167704 0,3
%A A167704 _Philippe Deléham_, Nov 10 2009
%E A167704 Corrected and extended by _Harvey P. Dale_, Aug 09 2015