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A353587
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Denominators of coefficients c(n) in product expansion of (tan x)/x = Product_{k>=1} 1 + c(k)*x^(2k).
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7
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3, 15, 105, 2835, 66825, 3648645, 383107725, 97692469875, 1856156927625, 5568470782875, 9056719980433125, 33283445928091734375, 1298054391195577640625, 3952575621190533915703125, 367589532770719654160390625, 112527407991036628824609375, 3842566358093920359949921875
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OFFSET
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1,1
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COMMENTS
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The coefficients of odd powers are zero since (tan x)/x is an even function.
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LINKS
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EXAMPLE
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(tan x)/x = (1 + 1/3*x^2)(1 + 2/15*x^4)(1 + 1/105*x^6)(1 + 53/2835*x^8)...
and this sequence lists the denominators of (1/3, 2/15, 1/105, 53/2835, ...).
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PROG
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(PARI) t=tan(x+O(x)^58)/x; vector(#t\2, n, c=polcoef(t, n*2); t/=1+c*x^(n*2); denominator(c))
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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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