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 A107068 #8 Jul 16 2018 19:29:42
%S A107068 1,-3,6,-10,16,-27,49,-92,172,-316,573,-1035,1874,-3406,6204,-11303,
%T A107068 20577,-37432,68072,-123800,225193,-409683,745342,-1355970,2466760,
%U A107068 -4487395,8163217,-14850196,27015092,-49145300,89404037,-162641499,295872778,-538243174,979156724,-1781254927,3240410561
%N A107068 Expansion of 1/((1+x)^3-x^4).
%H A107068 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (-3,-3,-1,1).
%F A107068 G.f.: 1/(1+3x+3x^2+x^3-x^4); a(n)=sum{k=0..n+4, (-1)^(n-k)*C(n+4, k)*sum{j=0..floor(k/4), C(k-3j, j)}}.
%t A107068 LinearRecurrence[{-3,-3,-1,1},{1,-3,6,-10},40] (* _Harvey P. Dale_, Jul 16 2018 *)
%Y A107068 Cf. A077990.
%K A107068 easy,sign
%O A107068 0,2
%A A107068 _Paul Barry_, May 10 2005