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A104042 Numerators of coefficients in expansion of x^-2*(1-exp(-2*x))^2. +0
3
4, -8, 28, -8, 248, -16, 508, -136, 584, -496, 16376, -16, 131056, -174752, 18724, -2056, 1048568, -1168, 4194296, -20336, 684784, -1945184, 67108856, -3856, 536870896, -715827872, 306783376, -19746976, 17179869152, -3198784, 8589934588, -134744072, 426829048, -91625968976 (list; graph; listen)
OFFSET

0,1

COMMENT

Suggested by Bill Gosper's remarkable identity (in a posting to math-fun list, Apr 14 2005): Product_{ n >= 0 } tanh(2^n x)^(1/2^n) = (1-exp(-2*x))^2.

MATHEMATICA

Numerator[ CoefficientList[ Series[x^-2*(1 - E^(-2x))^2, {x, 0, 33}], x]] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 20 2005)

CROSSREFS

Cf. A104097, A104007, A104042.

Sequence in context: A036720 A110132 A099513 this_sequence A117864 A020138 A090083

Adjacent sequences: A104039 A104040 A104041 this_sequence A104043 A104044 A104045

KEYWORD

sign,frac

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Apr 18 2005

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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