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A169721 a(n) = (2*(3*2^(n-1)-1))^2. 3

%I

%S 1,16,100,484,2116,8836,36100,145924,586756,2353156,9424900,37724164,

%T 150945796,603881476,2415722500,9663283204,38653919236,154617249796,

%U 618472144900,2473894871044,9895592067076,39582393434116,158329624068100,633318596935684

%N a(n) = (2*(3*2^(n-1)-1))^2.

%C A subsequence of the squares (A000290).

%H Vincenzo Librandi, <a href="/A169721/b169721.txt">Table of n, a(n) for n = 0..1000</a>

%H Alice V. Kleeva, <a href="/A169721/a169721a.jpg">Grid for this sequence</a>

%H Alice V. Kleeva, <a href="/A169721/a169721b.jpg">Illustration of initial terms</a>

%H Robert Munafo, <a href="http://www.mrob.com/pub/math/seq-a169720.html">Sequence A169720, and two others by Alice V. Kleeva</a>

%H Robert Munafo, <a href="/A169720/a169720.pdf">Sequence A169720, and two others by Alice V. Kleeva</a> [Cached copy, in pdf format, included with permission]

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).

%F a(n) = A033484(n)^2.

%F G.f.: (1+9*x+2*x^2)/(1-7*x+14*x^2-8*x^3). - _Bruno Berselli_, Dec 04 2012

%F a(n) = 7*a(n-1)-14*a(n-2)+8*a(n-3). - _Vincenzo Librandi_, Dec 04 2012

%t Table[(2(3*2^(n-1)-1))^2,{n,0,30}] (* _Harvey P. Dale_, Oct 29 2012 *)

%t CoefficientList[Series[(1+x)/((1-x)*(1-2*x)), {x, 0, 30}], x]^2 (* _Vincenzo Librandi_, Dec 04 2012 *)

%o (MAGMA) I:=[1,16,100]; [n le 3 select I[n] else 7*Self(n-1)-14*Self(n-2)+8*Self(n-3): n in [1..30]];// _Vincenzo Librandi_, Dec 04 2012

%Y Cf. A169720-A169727.

%K nonn,easy

%O 0,2

%A Alice V. Kleeva (alice27353(AT)gmail.com), Jan 19 2010

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Last modified October 20 04:37 EDT 2018. Contains 316378 sequences. (Running on oeis4.)