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 A176448 #21 Sep 08 2022 08:45:52
%S A176448 5,12,26,54,110,222,446,894,1790,3582,7166,14334,28670,57342,114686,
%T A176448 229374,458750,917502,1835006,3670014,7340030,14680062,29360126,
%U A176448 58720254,117440510,234881022,469762046,939524094,1879048190,3758096382
%N A176448 a(n) = 7*2^n - 2.
%C A176448 a(n) = 2*A086224(n-1) for n > 0 [Berselli - Librandi]. - _Vincenzo Librandi_, Aug 27 2010
%H A176448 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A176448 a(n) = 2*(a(n-1) + 1) with a(0)=5.
%F A176448 From _R. J. Mathar_, May 02 2010: (Start)
%F A176448 a(n)= 3*a(n-1) - 2*a(n-2).
%F A176448 G.f.: ( 5-3*x ) / ( (2*x-1)*(x-1) ). (End)
%F A176448 a(n) = A174317(n+3). - _R. J. Mathar_, Feb 21 2016
%e A176448 a(1) = 2*(5 + 1) = 12;
%e A176448 a(2) = 2*(12 + 1) = 26;
%e A176448 a(3) = 2*(26 + 1) = 54.
%t A176448 Table[7*2^n-2,{n,0,30}] (* or *) LinearRecurrence[{3,-2},{5,12},30] (* _Harvey P. Dale_, May 21 2017 *)
%o A176448 (Magma) [7*2^n-2: n in [0..100]]
%K A176448 nonn,easy
%O A176448 0,1
%A A176448 _Vincenzo Librandi_, Apr 18 2010