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 A080874 #8 Sep 18 2016 10:51:05
%S A080874 1,1,3,8,29,79,287,782,2841,7741,28123,76628,278389,758539,2755767,
%T A080874 7508762,27279281,74329081,270037043,735782048,2673091149,7283491399,
%U A080874 26460874447,72099131942,261935653321,713707828021,2592895658763
%N A080874 a(n)*a(n+3) - a(n+1)*a(n+2) = 5, given a(0)=a(1)=1, a(2)=3.
%H A080874 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,10,0,-1).
%F A080874 G.f.: (1+x-7x^2-2x^3)/(1-10x^2+x^4). a(n)=10a(n-2)-a(n-4). - _Michael Somos_, Mar 04 2003.
%F A080874 a(n) = ( - 1/24*3^(1/2)*2^(1/2) + 1/4 - 1/16*2^(1/2) + 1/8*3^(1/2))*(sqrt(3) + sqrt(2))^n + (1/24*3^(1/2)*2^(1/2) + 1/4 + 1/16*2^(1/2) + 1/8*3^(1/2))*(sqrt(3) - sqrt(2))^n + ( - 1/24*3^(1/2)*2^(1/2) - 1/8*3^(1/2) + 1/16*2^(1/2) + 1/4)*( - sqrt(3) - sqrt(2))^n + ( - 1/16*2^(1/2) + 1/4 + 1/24*3^(1/2)*2^(1/2) - 1/8*3^(1/2))*( - sqrt(3) + sqrt(2))^n [From _Richard Choulet_, Dec 04 2008]
%t A080874 LinearRecurrence[{0,10,0,-1},{1,1,3,8},30] (* _Harvey P. Dale_, Sep 18 2016 *)
%Y A080874 Cf. A080871, A080872, A080873, A080875.
%K A080874 nonn
%O A080874 0,3
%A A080874 _Paul D. Hanna_, Feb 22 2003