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A162256
a(n) = (2*n^3 + 5*n^2 - 3*n)/2.
2
2, 15, 45, 98, 180, 297, 455, 660, 918, 1235, 1617, 2070, 2600, 3213, 3915, 4712, 5610, 6615, 7733, 8970, 10332, 11825, 13455, 15228, 17150, 19227, 21465, 23870, 26448, 29205, 32147, 35280, 38610, 42143, 45885, 49842, 54020, 58425, 63063, 67940
OFFSET
1,1
COMMENTS
Row sums from A154680.
FORMULA
From Vincenzo Librandi, Mar 04 2012: (Start)
G.f.: x*(2 + 7*x - 3*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}, {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 *)
PROG
(PARI) n*(5*n-3)/2+n^3 \\ Charles R Greathouse IV, Jan 11 2012
CROSSREFS
Sequence in context: A318914 A346546 A327941 * A229013 A323685 A336209
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jun 29 2009
STATUS
approved