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A151932
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a(n) = 2^(2*n)*(n!)^2*Product_{e_k} binomial(2*e_k, e_k) where 2n = Product p_k^e_k is the prime factorization of 2n.
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2
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8, 384, 9216, 2949120, 58982400, 25480396800, 1664719257600, 7457942274048000, 414235422307123200, 165694168922849280000, 26731992586219683840000, 153976277296625378918400000, 10408796345251875614883840000, 24481489004032411446206791680000, 14688893402419446867724075008000000
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OFFSET
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1,1
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LINKS
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EXAMPLE
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n = 5: 2n = 10 = 2^1*5^1, a(5) = 2^10*120^2*2*2 = 58982400.
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MATHEMATICA
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Array[2^(2#) (#!)^2 Times@@(Binomial[2#, # ]&/@FactorInteger[2# ][[All, 2]])&, 12] (* Floris P. van Doorn and Jasper Mulder (florisvandoorn(AT)hotmail.com), Oct 12 2009 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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More terms from Floris P. van Doorn and Jasper Mulder (florisvandoorn(AT)hotmail.com), Oct 12 2009
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STATUS
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approved
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