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 A063270 #20 Jun 17 2025 00:43:49
%S A063270 2,82,6562,531442,43046722,3486784402,282429536482,22876792454962,
%T A063270 1853020188851842,150094635296999122,12157665459056928802,
%U A063270 984770902183611232882,79766443076872509863362,6461081889226673298932242,523347633027360537213511522,42391158275216203514294433202
%N A063270 a(n) = 9^(2*n) + 1.
%H A063270 Harry J. Smith, <a href="/A063270/b063270.txt">Table of n, a(n) for n = 0..100</a>
%H A063270 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (82,-81).
%F A063270 a(n) = 82*a(n-1) - 81*a(n-2), a(0)=2, a(1)=82. - _Harvey P. Dale_, Jul 31 2013
%F A063270 From _Elmo R. Oliveira_, Jun 16 2025: (Start)
%F A063270 G.f.: 2*(1-41*x)/((x-1)*(81*x-1)).
%F A063270 E.g.f.: exp(x)*(exp(80*x) + 1).
%F A063270 a(n) = A062396(2*n). (End)
%t A063270 9^(2*Range[0,20])+1 (* or *) LinearRecurrence[{82,-81},{2,82},20] (* _Harvey P. Dale_, Jul 31 2013 *)
%o A063270 (PARI) a(n) = 9^(2*n) + 1;
%Y A063270 Cf. A062396, A063271.
%K A063270 easy,nonn
%O A063270 0,1
%A A063270 _Jason Earls_, Jul 12 2001
%E A063270 More terms from _Harvey P. Dale_, Jul 31 2013