A162267 a(n) = (2*n^3 + 5*n^2 + 5*n)/2.

6, 23, 57, 114, 200, 321, 483, 692, 954, 1275, 1661, 2118, 2652, 3269, 3975, 4776, 5678, 6687, 7809, 9050, 10416, 11913, 13547, 15324, 17250, 19331, 21573, 23982, 26564, 29325, 32271, 35408, 38742, 42279, 46025, 49986, 54168, 58577, 63219

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Formula

Row sums from A155705: a(n) = Sum_{m=1..n} (2*m*n + m + n + 2).

From Vincenzo Librandi, Mar 05 2012: (Start)

G.f.: x*(6 - x + x^2)/(1-x)^4.

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

Mathematica

LinearRecurrence[{4, -6, 4, -1}, {6, 23, 57, 114}, 50] (* or *) CoefficientList[Series[(6-x+x^2)/(1-x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Mar 05 2012 *)

Crossrefs

Cf. A155705.

Sequence in context: A234729 A273500 A189713 * A009017 A273540 A273214

Adjacent sequences: A162264 A162265 A162266 * A162268 A162269 A162270

Keyword

nonn,easy

Author

Vincenzo Librandi, Jun 29 2009

Extensions

New name from Vincenzo Librandi, Mar 05 2012

Status

approved