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 A127261 #23 Feb 26 2024 01:58:34
%S A127261 2,2,24,68,376,1432,6624,27568,121376,518432,2250624,9685568,41877376,
%T A127261 180610432,779994624,3366093568,14532133376,62725202432,270771738624,
%U A127261 1168795501568,5045308389376
%N A127261 a(0)=2, a(1)=2, a(n) = 2*a(n-1) + 10*a(n-2).
%H A127261 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2, 10).
%F A127261 G.f.: (2*(x-1))/(2*x(5*x+1)-1). - _Harvey P. Dale_, Oct 15 2013
%p A127261 a[0]:=2:a[1]:=2:for i from 2 to 40 do a[i]:=2*a[i-1]+10*a[i-2] od: seq(a[n],n=0..40);
%t A127261 LinearRecurrence[{2,10},{2,2},30] (* or *) CoefficientList[Series[(2*(x-1))/(2*x(5*x+1)-1),{x,0,30}],x] (* _Harvey P. Dale_, Oct 15 2013 *)
%o A127261 (Sage) [lucas_number2(n,2,-10) for n in range(0, 21)] # _Zerinvary Lajos_, Apr 30 2009
%K A127261 easy,nonn
%O A127261 0,1
%A A127261 _Miklos Kristof_, Mar 27 2007