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A144659
a(n) = A001516(n)/2.
0
0, 0, 3, 60, 990, 16485, 292215, 5602338, 116549370, 2627202105, 63960690420, 1675359272730, 47031228602358, 1409683851264780, 44956320071089245, 1520493296271210030, 54376042036599780570, 2050556012681642525763, 81336729496634645414265, 3385729099078381669910310
OFFSET
0,3
FORMULA
Also a(n) = 3*A144507(n).
Also a(n) = Sum_{k} binomial(k-n,2) T(n,k) where T(n,k) is the triangle in A144331.
CROSSREFS
Sequence in context: A006432 A360577 A195550 * A115490 A065889 A183251
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 30 2009
STATUS
approved