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%I #27 Feb 18 2024 03:33:07
%S 1,22,145,715,3151,13207,54055,218695,879751,3528967,14135815,
%T 56583175,226412551,905809927,3623559175,14494875655,57980780551,
%U 231925678087,927707824135,3710841520135,14843386527751,59373587005447,237494429810695,949977882820615
%N a(n) = (3*2^(n-1)-1)*(18*2^(n-1)-7).
%H Vincenzo Librandi, <a href="/A169722/b169722.txt">Table of n, a(n) for n = 0..1000</a>
%H Alice V. Kleeva, <a href="/A169722/a169722a.jpg">Grid for this sequence</a>
%H Alice V. Kleeva, <a href="/A169722/a169722b.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 G.f.: (1+15*x+5*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 LinearRecurrence[{7, -14, 8}, {1, 22, 145}, 30] (* _Vincenzo Librandi_, Dec 04 2012 *)
%o (Magma) I:=[1,22,145]; [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
%o (Maxima) makelist(coeff(taylor((1+15*x+5*x^2)/(1-7*x+14*x^2-8*x^3), x, 0, n), x, n), n, 0, 23); /* _Bruno Berselli_, Dec 04 2012 */
%Y Cf. A169720-A169727, A033484.
%K nonn,easy
%O 0,2
%A Alice V. Kleeva (alice27353(AT)gmail.com), Jan 19 2010
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