%I #44 Sep 08 2022 08:44:45

%S 4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,

%T 131072,262144,524288,1048576,2097152,4194304,8388608,16777216,

%U 33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592

%N Pisot sequences E(4,8), L(4,8), P(4,8), T(4,8).

%C Subsequence of A051916. - _Reinhard Zumkeller_, Mar 20 2010

%H Vincenzo Librandi, <a href="/A020707/b020707.txt">Table of n, a(n) for n = 0..238</a>

%H Tanya Khovanova, <a href="https://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Di#divseq">Index to divisibility sequences</a>

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (2).

%F a(n) = 2^(n+2).

%F a(n) = 2*a(n-1).

%F G.f.: 4/(1-2*x). - _Philippe Deléham_, Nov 23 2008

%F E.g.f.: 4*exp(2*x). - _Stefano Spezia_, May 15 2021

%t 2^(Range[0, 50] + 2) (* _Vladimir Joseph Stephan Orlovsky_, Jun 09 2011 *)

%o (Magma) [2^(n+2): n in [0..40]]; // _Vincenzo Librandi_, Apr 28 2011

%o (PARI) a(n)=4<<n \\ _Charles R Greathouse IV_, Apr 08 2012

%Y Subsequence of A000079. See A008776 for definitions of Pisot sequences.

%Y Cf. A051916.

%K nonn,easy

%O 0,1

%A _David W. Wilson_