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A353583
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Numerators of coefficients c(n) in product expansion of 1 + tan x = Product_{k>=1} 1 + c(k)*x^k.
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12
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1, 0, 1, -1, 7, -7, 199, -71, 484, -368, 187909, -610103, 2068657, -63614, 1530164189, -1715846683, 7628902283, -125125345078, 9521826231889, -17921564328719, 291162274608871, -47147385565688, 552647133893696333, -36898601487519532, 4761064630028162378
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OFFSET
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1,5
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COMMENTS
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See A353584 for the denominators, and A353586 for the analog for (tan x)/x.
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LINKS
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EXAMPLE
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1 + tan x = (1 + x)(1 + 1/3*x^3)(1 - 1/3*x^4/3)(1 + 7/15*x^5)(1 - 7/15*x^5)(...),
and this sequence lists the numerators of (1, 0, 1/3, -1/3, 7/15, -7/15, ...).
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PROG
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(PARI) t=1+tan(x+O(x)^29); vector(#t-1, n, c=polcoef(t, n); t/=1+c*x^n; numerator(c))
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CROSSREFS
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KEYWORD
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sign,frac
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AUTHOR
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STATUS
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approved
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