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 A155599 #27 Mar 10 2022 05:23:21
%S A155599 1,7,61,505,4081,32737,262081,2097025,16776961,134217217,1073740801,
%T A155599 8589932545,68719472641,549755805697,4398046494721,35184372056065,
%U A155599 281474976645121,2251799813554177,18014398509219841,144115188075331585
%N A155599 a(n) = 8^n - 2^n + 1^n.
%H A155599 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (11,-26,16).
%F A155599 G.f.: 1/(1-8*x) - 1/(1-2*x) + 1/(1-x).
%F A155599 E.g.f.: e^(8*x) - e^(2*x) + e^x.
%F A155599 a(n) = 10*a(n-1) - 16*a(n-2) + 7 with a(0)=1, a(1)=7 - _Vincenzo Librandi_, Jul 21 2010
%F A155599 a(n) = A248217(n)+1. - _R. J. Mathar_, Mar 10 2022
%t A155599 Table[8^n-2^n+1,{n,0,30}] (* or *) LinearRecurrence[{11,-26,16},{1,7,61},30] (* _Harvey P. Dale_, Feb 25 2014 *)
%o A155599 (PARI) a(n)=8^n-2^n+1 \\ _Charles R Greathouse IV_, Sep 24 2015
%Y A155599 Cf. A074501, A020515, A155588, A155590, A155592, A155593, A155594, A155596, A155597, A155598.
%K A155599 nonn,easy
%O A155599 0,2
%A A155599 _Mohammad K. Azarian_, Jan 25 2009