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 A175806 #35 Apr 22 2025 06:32:04
%S A175806 27,54,108,216,432,864,1728,3456,6912,13824,27648,55296,110592,221184,
%T A175806 442368,884736,1769472,3538944,7077888,14155776,28311552,56623104,
%U A175806 113246208,226492416,452984832,905969664,1811939328,3623878656,7247757312,14495514624,28991029248
%N A175806 a(n) = 27*2^n.
%C A175806 The squares of these terms appear in A159274.
%H A175806 Vincenzo Librandi, <a href="/A175806/b175806.txt">Table of n, a(n) for n = 0..1000</a>
%H A175806 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (2).
%F A175806 G.f.: 27/(1-2*x).
%F A175806 From _Elmo R. Oliveira_, Sep 14 2024: (Start)
%F A175806 E.g.f.: 27*exp(2*x).
%F A175806 a(n) = 27*A000079(n).
%F A175806 a(n) = 2*a(n-1) for n > 0. (End)
%t A175806 Table[27 2^n, {n, 0, 40}] (* _Vincenzo Librandi_, Sep 30 2013 *)
%t A175806 NestList[2#&,27,30] (* _Harvey P. Dale_, Apr 17 2022 *)
%o A175806 (Magma) [27*2^n: n in [0..40]];
%o A175806 (PARI) apply(n -> 27*2^n, [0..40]) \\ _Satish Bysany_, Mar 06 2017
%Y A175806 Cf. A000079, A159274.
%K A175806 nonn,easy
%O A175806 0,1
%A A175806 _Vincenzo Librandi_, Dec 05 2010