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 A275163 #15 Aug 08 2021 14:44:38
%S A275163 7,33,85,189,397,813,1645,3309,6637,13293,26605,53229,106477,212973,
%T A275163 425965,851949,1703917,3407853,6815725,13631469,27262957,54525933,
%U A275163 109051885,218103789,436207597,872415213,1744830445,3489660909,6979321837,13958643693
%N A275163 a(n) = 13*2^(n+1) - 19.
%C A275163 Most terms in even positions of A278066 are terms in this sequence.
%H A275163 Harvey P. Dale, <a href="/A275163/b275163.txt">Table of n, a(n) for n = 0..1000</a>
%H A275163 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A275163 a(0) = 7; a(n) = 2*a(n-1) + 19 for n>=1.
%F A275163 G.f.: (12*x+7)/((1-2*x)*(1-x)).
%t A275163 NestList[2#+19&,7,30] (* or *) LinearRecurrence[{3,-2},{7,33},30] (* _Harvey P. Dale_, Aug 08 2021 *)
%Y A275163 Cf. A278066.
%K A275163 nonn
%O A275163 0,1
%A A275163 _Nathan Fox_, Nov 13 2016