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A162263
a(n) = (2*n^3 + 5*n^2 + 11*n)/2.
1
9, 29, 66, 126, 215, 339, 504, 716, 981, 1305, 1694, 2154, 2691, 3311, 4020, 4824, 5729, 6741, 7866, 9110, 10479, 11979, 13616, 15396, 17325, 19409, 21654, 24066, 26651, 29415, 32364, 35504, 38841, 42381, 46130, 50094, 54279, 58691, 63336
OFFSET
1,1
FORMULA
Row sums from A154631: a(n) = Sum_{m=1..n} (2*m*n + m + n + 5).
From _Vincenzo Librandi, Mar 05 2012: (Start)
G.f.: x*(9 - 7*x + 4*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}, {9, 29, 66, 126}, 50] (* or *) CoefficientList[Series[(9-7*x+4*x^2)/(1-x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Mar 05 2012 *)
CROSSREFS
Cf. A154631.
Sequence in context: A136392 A272732 A272740 * A272784 A272807 A316602
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Jun 29 2009
EXTENSIONS
New name from Vincenzo Librandi, Mar 05 2012
STATUS
approved