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A162257 a(n) = (2*n^3 + 5*n^2 - 11*n)/2. 1

%I

%S -2,7,33,82,160,273,427,628,882,1195,1573,2022,2548,3157,3855,4648,

%T 5542,6543,7657,8890,10248,11737,13363,15132,17050,19123,21357,23758,

%U 26332,29085,32023,35152,38478,42007,45745,49698,53872,58273,62907,67780

%N a(n) = (2*n^3 + 5*n^2 - 11*n)/2.

%H Vincenzo Librandi, <a href="/A162257/b162257.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 A155550: a(n) = Sum_{m=1..n} 2*m*n + m + n - 6.

%F From _Vincenzo Librandi_, Mar 04 2012: (Start)

%F G.f.: x*(-2 + 15*x - 7*x^2)/(1-x)^4.

%F a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)

%p A162257:=n->(2*n^3+5*n^2-11*n)/2: seq(A162257(n), n=1..80); # _Wesley Ivan Hurt_, Jan 30 2017

%t CoefficientList[Series[(-2+15*x-7*x^2)/(1-x)^4,{x,0,40}],x] (* or *) LinearRecurrence[{4, -6, 4, -1}, {-2, 7, 33, 82}, 50] (* _Vincenzo Librandi_, Mar 04 2012 *)

%Y Cf. A155550.

%K sign,easy

%O 1,1

%A _Vincenzo Librandi_, Jun 29 2009

%E New name from _Vincenzo Librandi_, Mar 04 2012

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Last modified May 17 09:03 EDT 2021. Contains 343969 sequences. (Running on oeis4.)