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A158620
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Partial products of A068601.
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4
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7, 182, 11466, 1421784, 305683560, 104543777520, 53421870312720, 38891121587660160, 38852230466072499840, 51673466519876424787200, 89240076679826585607494400, 195971208388899181994057702400
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OFFSET
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2,1
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COMMENTS
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Also the determinant of the n X n matrix given by m(i,j) = i^3 if i=j and 1 otherwise. For example, Det[{{1,1,1, 1},{1,8,1,1},{1,1,27,1},{1,1,1,64}}] = 11466 = a(4). - John M. Campbell, May 20 2011
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LINKS
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FORMULA
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Product_{k=2..n} (k^3-1) = Product_{k=2..n} A068601(k).
a(n) ~ 2^(3/2) * sqrt(Pi) * cosh(sqrt(3)*Pi/2) * n^(3*n+3/2) / (3 * exp(3*n)). - Vaclav Kotesovec, Jul 11 2015
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EXAMPLE
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a(2) = 2^3-1 = 7.
a(3) = (2^3-1)*(3^3-1) = 7 * 26 = 182.
a(4) = (2^3-1)*(3^3-1)*(4^3-1) = 7 * 26 * 63 = 11466.
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MATHEMATICA
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Rest[FoldList[Times, 1, Range[2, 15]^3-1]] (* Harvey P. Dale, Apr 18 2015 *)
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PROG
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(PARI) a(n) = prod(k = 2, n, k^3 - 1); \\ Michel Marcus, Sep 29 2013
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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