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A011890 [ n(n-1)(n-2)/8 ]. 0
0, 0, 0, 0, 3, 7, 15, 26, 42, 63, 90, 123, 165, 214, 273, 341, 420, 510, 612, 726, 855, 997, 1155, 1328, 1518, 1725, 1950, 2193, 2457, 2740, 3045, 3371, 3720, 4092, 4488, 4908, 5355, 5827, 6327, 6854, 7410 (list; graph; refs; listen; history; internal format)
OFFSET

0,5

FORMULA

a(n) = +3*a(n-1) -3*a(n-2) +a(n-3) +a(n-8) -3*a(n-9) +3*a(n-10) -a(n-11). G.f.: x^4*(3-2*x+3*x^2-x^3+2*x^4+x^6) / ( (-1+x)^4*(1+x)*(1+x^2)*(1+x^4) ). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 15 2010]

CROSSREFS

Sequence in context: A144643 A034757 A078869 * A131076 A001648 A051054

Adjacent sequences:  A011887 A011888 A011889 * A011891 A011892 A011893

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 17 18:57 EST 2012. Contains 206074 sequences.