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 A134752 #19 Jan 04 2021 13:56:03
%S A134752 5,29,245,2189,19685,177149,1594325,14348909,129140165,1162261469,
%T A134752 10460353205,94143178829,847288609445,7625597484989,68630377364885,
%U A134752 617673396283949,5559060566555525,50031545098999709,450283905890997365,4052555153018976269
%N A134752 a(n) = 3^(2*n-1) + 2.
%C A134752 Suggested by a posting from _Luis H. Gallardo_ to the Number Theory List, Jan 14 2008
%H A134752 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,-9).
%F A134752 a(1)=5, a(2)=29, a(n)=10*a(n-1)-9*a(n-2). - _Harvey P. Dale_, Dec 08 2015
%t A134752 3^(2*Range[20]-1)+2 (* or *) LinearRecurrence[{10, -9}, {5, 29}, 20] (* _Harvey P. Dale_, Dec 08 2015 *)
%Y A134752 Cf. A134753.
%K A134752 nonn,easy
%O A134752 1,1
%A A134752 _N. J. A. Sloane_, Jan 28 2008