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A159964
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a(n) = 2^n*(1-n).
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6
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1, 0, -4, -16, -48, -128, -320, -768, -1792, -4096, -9216, -20480, -45056, -98304, -212992, -458752, -983040, -2097152, -4456448, -9437184, -19922944, -41943040, -88080384, -184549376, -385875968, -805306368, -1677721600, -3489660928
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: (1-4x)/(1-2x)^2.
E.g.f.: U(0) where U(k)= 1 - 2*x/(2 - 4/(2 - (k+1)/U(k+1))) ; (continued fraction, 3-step). - Sergei N. Gladkovskii, Oct 18 2012
Sum_{n>=2} 1/a(n) = -log(2)/2.
Sum_{n>=2} (-1)^n/a(n) = -log(3/2)/2. (End)
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MATHEMATICA
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LinearRecurrence[{4, -4}, {1, 0}, 30] (* Harvey P. Dale, May 02 2016 *)
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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STATUS
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approved
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