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%I #22 Sep 08 2022 08:44:57
%S 1,3,13,49,161,481,1345,3585,9217,23041,56321,135169,319489,745473,
%T 1720321,3932161,8912897,20054017,44826625,99614721,220200961,
%U 484442113,1061158913,2315255809,5033164801,10905190401,23555211265,50734301185,108984795137
%N a(n) = T(n,n), array T given by A048472.
%H Vincenzo Librandi, <a href="/A048482/b048482.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-18,20,-8).
%F a(n) = 2 * A001788(n) + 1.
%F a(n) = (n^2+n)*2^(n-1) + 1. - _Ralf Stephan_, Sep 02 2003
%F G.f.: -(8*x^3-10*x^2+4*x-1) / ((x-1)*(2*x-1)^3). - _Colin Barker_, Nov 26 2014
%F a(0)=1, a(1)=3, a(2)=13, a(3)=49, a(n)=7*a(n-1)-18*a(n-2)+ 20*a(n-3)- 8*a(n-4). - _Harvey P. Dale_, Feb 02 2015
%t LinearRecurrence[{7,-18,20,-8},{1,3,13,49},30] (* _Harvey P. Dale_, Feb 02 2015 *)
%o (Magma) [(n^2+n)*2^(n-1) + 1: n in [0..30]]; // _Vincenzo Librandi_, Sep 23 2011
%o (PARI) Vec(-(8*x^3-10*x^2+4*x-1)/((x-1)*(2*x-1)^3) + O(x^100)) \\ _Colin Barker_, Nov 26 2014
%Y Cf. A002999, A003013, A001787, A005183, A001788.
%K nonn,easy
%O 0,2
%A _Clark Kimberling_
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