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 A165230 #13 Jan 03 2024 23:53:14
%S A165230 1,7,91,1225,16513,222607,3000907,40454449,545355937,7351801975,
%T A165230 99107736091,1336045691449,18010885527649,242800077546943,
%U A165230 3273124886963659,44124147874662625,594826196036531137,8018697709388797543,108097984559187447643,1457240899862902684201
%N A165230 a(0)=1, a(1)=7, a(n)=14*a(n-1)-7*a(n-2) for n>1 .
%H A165230 Harvey P. Dale, <a href="/A165230/b165230.txt">Table of n, a(n) for n = 0..885</a>
%H A165230 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (14,-7).
%F A165230 G.f.: (1-7*x)/(1-14*x+7*x^2) .
%F A165230 a(n) = (1/2)*((7+sqrt(42))^n+(7-sqrt(42))^n). [_Paolo P. Lava_, Sep 16 2009]
%t A165230 LinearRecurrence[{14,-7},{1,7},20] (* _Harvey P. Dale_, Dec 18 2016 *)
%K A165230 nonn,easy
%O A165230 0,2
%A A165230 _Philippe Deléham_, Sep 09 2009
%E A165230 More terms from _Harvey P. Dale_, Dec 18 2016