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A078973
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Total dimension of the homology of a free 2-step nilpotent Lie algebra of rank n.
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0
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2, 6, 36, 420, 9800, 452760, 41835024, 7691667984, 2828336198688, 2073619375892064, 3040584296923128384, 8898500292240756664896, 52084270468105185237918848, 608812309050346291991694422400
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OFFSET
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1,1
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LINKS
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FORMULA
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a(n) = 2^ceiling(n/2)*f(floor((n-1)/2))*f(floor(n/2)), where f(n)= Product_{i=1..n} (4*i)!*i!^2/((2*i)!)^3.
a(n) ~ K*2^(n^2/2)*n^(1/8), where K=1.3814... - Nordine Fahssi, Jan 17 2019
K = 1.38143139396100192327615434710888289668811010590733/
41912628937302462176044631403587011199108546012939...
(End)
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MAPLE
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f := proc(n) local i: mul((4*i)!*i!^2/((2*i)!)^3, i=1..n): end:seq(2^ceil(n/2)*f(floor((n-1)/2))*f(floor(n/2)), n=1..20);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jan 12 2003
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STATUS
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approved
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