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A007518
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[ n(n+2)(2n-1)/8 ].
(Formerly M2776)
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1
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0, 3, 9, 21, 39, 66, 102, 150, 210, 285, 375, 483, 609, 756, 924, 1116, 1332, 1575, 1845, 2145, 2475, 2838, 3234, 3666, 4134, 4641, 5187, 5775, 6405, 7080, 7800, 8568, 9384, 10251, 11169, 12141, 13167, 14250, 15390
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| From a problem on p. 151 of J. Rec. Math., 7 (1975).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| 3*A002623(n) for n>0. - M. F. Hasler, Sep 15 2009
G.f.:3*x/((x+1)*(x-1)^4) [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 10 2009]
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CROSSREFS
| Column 4 of triangle A094953.
Sequence in context: A014857 A177817 A112039 * A029494 A059774 A064999
Adjacent sequences: A007515 A007516 A007517 * A007519 A007520 A007521
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Robert G. Wilson v (rgwv(AT)rgwv.com)
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