|
%I #15 Aug 31 2018 02:56:40
%S 7,25,60,118,205,327,490,700,963,1285,1672,2130,2665,3283,3990,4792,
%T 5695,6705,7828,9070,10437,11935,13570,15348,17275,19357,21600,24010,
%U 26593,29355,32302,35440,38775,42313,46060,50022,54205,58615,63258
%N a(n) = (2*n^3 + 5*n^2 + 7*n)/2.
%H Vincenzo Librandi, <a href="/A162264/b162264.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 Row sums from A154681: a(n) = Sum_{m=1..n} (2*m*n + m + n + 3).
%F From _Vincenzo Librandi_, Mar 05 2012: (Start)
%F G.f.: x*(7 - 3*x + 2*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}, {7, 25, 60, 118}, 50] (* or *) CoefficientList[Series[(7-3*x+2*x^2)/(1-x)^4,{x,0,40}],x] (* _Vincenzo Librandi_, Mar 05 2012 *)
%Y Cf. A154681.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Jun 29 2009
%E New name from _Vincenzo Librandi_, Mar 05 2012
|
