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 A022323 #11 Aug 25 2017 23:36:14
%S A022323 1,9,11,21,33,55,89,145,235,381,617,999,1617,2617,4235,6853,11089,
%T A022323 17943,29033,46977,76011,122989,199001,321991,520993,842985,1363979,
%U A022323 2206965,3570945,5777911,9348857
%N A022323 a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 9.
%H A022323 G. C. Greubel, <a href="/A022323/b022323.txt">Table of n, a(n) for n = 0..1000</a>
%H A022323 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-1).
%F A022323 From _R. J. Mathar_, Apr 07 2011: (Start)
%F A022323 G.f.: (1+7*x-7*x^2)/((1-x)*(1-x-x^2)).
%F A022323 a(n) = A022367(n) - 1. (End)
%F A022323 a(n) = 2*F(n+2) + 6*F(n) - 1, where F = A000045. - _G. C. Greubel_, Aug 25 2017
%t A022323 LinearRecurrence[{2,0,-1}, {1,9,11}, 50] (* _G. C. Greubel_, Aug 25 2017 *)
%o A022323 (PARI) x='x+O('x^50); Vec((1+7*x-7*x^2)/((1-x)*(1-x-x^2))) \\ _G. C. Greubel_, Aug 25 2017
%K A022323 nonn
%O A022323 0,2
%A A022323 _N. J. A. Sloane_