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 A214091 #30 Sep 08 2022 08:46:02
%S A214091 -3,-5,-7,-5,17,115,473,1675,5537,17635,54953,168955,515057,1561555,
%T A214091 4717433,14217835,42784577,128615875,386371913,1160164315,3482590097,
%U A214091 10451964595,31364282393,94109624395,282362427617,847154391715,2541597392873,7625060614075,22875718713137
%N A214091 a(n) = 3^n - 2^(n+2).
%C A214091 The subsequence of (positive or negative) primes begins: -3, -5, -7, -5, 17, no more through the composite a(116) (which is near 2.2*10^55). - _Jonathan Vos Post_, Jul 03 2012
%H A214091 Vincenzo Librandi, <a href="/A214091/b214091.txt">Table of n, a(n) for n = 0..1000</a>
%H A214091 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5,-6).
%F A214091 G.f.: ( -3+10*x ) / ( (3*x-1)*(2*x-1) ). - _R. J. Mathar_, Jul 07 2012
%F A214091 a(n) = 5*a(n-1) - 6*a(n-2) for n>1. - _Vincenzo Librandi_, Jun 18 2014
%t A214091 Table[3^n - 2^(n+2), {n, 0, 30}] (* or *) CoefficientList[Series[(-3 + 10 x)/((3 x - 1) (2 x - 1)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jun 17 2014 *)
%o A214091 (Magma) [3^n - 2^(n+2): n in [0..30]]; // _Vincenzo Librandi_, Jun 18 2014
%Y A214091 Cf. A001047 (3^n - 2^n), A003063 (3^n - 2^(n+1)).
%K A214091 sign,easy
%O A214091 0,1
%A A214091 _Alex Ratushnyak_, Jul 03 2012