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%I #21 Aug 30 2018 23:19:42
%S 2,15,45,98,180,297,455,660,918,1235,1617,2070,2600,3213,3915,4712,
%T 5610,6615,7733,8970,10332,11825,13455,15228,17150,19227,21465,23870,
%U 26448,29205,32147,35280,38610,42143,45885,49842,54020,58425,63063,67940
%N a(n) = (2*n^3 + 5*n^2 - 3*n)/2.
%C Row sums from A154680.
%H Vincenzo Librandi, <a href="/A162256/b162256.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F From _Vincenzo Librandi_, Mar 04 2012: (Start)
%F G.f.: x*(2 + 7*x - 3*x^2)/(1-x)^4.
%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
%t LinearRecurrence[{4,-6,4,-1}, {2, 15, 45, 98}, 50] (* or *) CoefficientList[Series[(2+7*x-3*x^2)/(1-x)^4,{x,0,39}],x] (* _Vincenzo Librandi_, Mar 04 2012 *)
%o (PARI) n*(5*n-3)/2+n^3 \\ _Charles R Greathouse IV_, Jan 11 2012
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Jun 29 2009
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