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A103207
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a(n)=(-1)^floor(n/2)/det(M_n) where M_n is the n X n matrix of terms 1/(i+j)! i and j ranging from 1 to n.
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1
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n)=(1/2^n)*{prod(k=1, n, (2*k)!/k!)}^2.
a(n) ~ A * 2^(2*n^2 + 2*n + 5/12) * n^(n^2 + n + 1/12) / exp(3*n^2/2 + n + 1/12), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, May 01 2015
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MAPLE
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MATHEMATICA
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Table[1/2^n*(Product[(2*k)!/k!, {k, 1, n}])^2, {n, 0, 10}] (* Vaclav Kotesovec, May 01 2015 *)
Table[2^(2*n^2 + n - 1/12) * Glaisher^3 * BarnesG[n+3/2]^2 / (E^(1/4) * Pi^(n+1/2)), {n, 0, 10}] (* Vaclav Kotesovec, May 01 2015 *)
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PROG
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(PARI) a(n)=(1/2^n)*prod(k=1, n, (2*k)!/k!)^2
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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