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 A081337 #14 Jul 14 2023 15:30:13
%S A081337 1,6,40,288,2176,16896,133120,1056768,8421376,67239936,537395200,
%T A081337 4297064448,34368126976,274911461376,2199157473280,17592722915328,
%U A081337 140739635838976,1125908496777216,9007233614479360,72057731476881408
%N A081337 a(n) = (8^n + 4^n)/2.
%C A081337 Binomial transform of A081336. 6th binomial transform of (1,0,4,0,16,0,64,....).
%H A081337 Vincenzo Librandi, <a href="/A081337/b081337.txt">Table of n, a(n) for n = 0..200</a>
%H A081337 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (12,-32).
%F A081337 a(n) = 12*a(n-1) -32*a(n-2), a(0)=1, a(1)=6.
%F A081337 G.f.: (1-6*x)/((1-4*x)*(1-8*x)).
%F A081337 E.g.f.: exp(6*x) * cosh(2*x).
%t A081337 CoefficientList[Series[(1 - 6 x) / ((1 - 4 x) (1 - 8 x)),{x, 0, 20}], x] (* _Vincenzo Librandi_, Aug 08 2013 *)
%o A081337 (Magma) [(8^n+4^n)/2: n in [0..25]]; // _Vincenzo Librandi_, Aug 08 2013
%Y A081337 Cf. A081338.
%K A081337 nonn,easy
%O A081337 0,2
%A A081337 _Paul Barry_, Mar 18 2003