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 A081708 #10 Feb 22 2016 11:35:58 %S A081708 2,1,129,193,8449,20801,561537,1892801,37831169,158970433,2580165249, %T A081708 12754272961,177884848897,994158318401,12378788647809,76004921025473, %U A081708 868247394485249,5732562340115521,61300395587171457,428184385354564801,4351409702933538049 %N A081708 a(n) = a(n-1) + 64*a(n-2) starting with a(0) = 2 and a(1) = 1. %H A081708 Colin Barker, <a href="/A081708/b081708.txt">Table of n, a(n) for n = 0..1000</a> %H A081708 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,64). %F A081708 a(n) = ((1 + sqrt(257))/2)^n + ((1 - sqrt(257))/2)^n. %F A081708 G.f.: (2-x) / (1-x-64*x^2). - _Colin Barker_, Feb 22 2016 %o A081708 (PARI) a(n) = my(w = quadgen(257)); w^n + (1 - w)^n; %o A081708 (PARI) Vec((2-x)/(1-x-64*x^2) + O(x^30)) \\ _Colin Barker_, Feb 22 2016 %Y A081708 Cf. A072265. %K A081708 nonn,easy %O A081708 0,1 %A A081708 Helmut Schmiedel (a.positiv(AT)web.de), Apr 03 2003 %E A081708 More terms from _Michel Marcus_, Aug 24 2013