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A181993
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Denominator of (4^n*(4^n-1)/2)*B_{2n}/(2n)!, B_{n} Bernoulli number.
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1
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1, 2, 6, 15, 630, 2835, 155925, 6081075, 1277025750, 10854718875, 1856156927625, 194896477400625, 2900518163668125, 3698160658676859375, 1298054391195577640625, 263505041412702261046875, 245059688513813102773593750, 4043484860477916195764296875
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OFFSET
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0,2
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COMMENTS
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Numerator is (-1)^(n+1)*A046990(n).
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LINKS
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FORMULA
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a(n) = denominator of (1/Pi)*Integral(x>=0, (sin(x)/x)^(2*n)*sin(2*n*x)*tan(x)).
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MAPLE
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A181993 := n -> denom((4^n*(4^n-1)/2)*bernoulli(2*n)/(2*n)!);
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MATHEMATICA
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a[n_] := Denominator[4^n (4^n-1)/2 BernoulliB[2n]/(2n)!];
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PROG
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(PARI) a(n) = denominator((4^n*(4^n-1)/2)*bernfrac(2*n)/(2*n)!); \\ Michel Marcus, Jun 18 2019
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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