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A171501
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Inverse binomial transform of A084640.
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1
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0, 1, 3, -1, 7, -9, 23, -41, 87, -169, 343, -681, 1367, -2729, 5463, -10921, 21847, -43689, 87383, -174761, 349527, -699049, 1398103, -2796201, 5592407, -11184809, 22369623, -44739241, 89478487, -178956969, 357913943, -715827881
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OFFSET
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0,3
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COMMENTS
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a(n) and differences are
0, 1, 3, -1, 7, -9,
1, 2, -4, 8, -16, 32, =(-1)^(n+1) * A171449(n),
1, -6, 12, -24, 48, -96,
-7, 18, -36, 72, -144, 288,
25, -54, 108, -216, 432, -864,
Vertical: 1) 0 followed with A168589(n).
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LINKS
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FORMULA
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G.f.: x*(1+4*x) / ( (1+2*x)*(1-x) ). - R. J. Mathar, Jun 14 2011
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MATHEMATICA
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CoefficientList[Series[x*(1 + 4*x)/((1 + 2*x)*(1 - x)), {x, 0, 30}], x]
LinearRecurrence[{-1, 2}, {0, 1, 3}, 40] (* Harvey P. Dale, Jan 14 2020 *)
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PROG
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(Magma) I:=[0, 1, 3]; [n le 3 select I[n] else -Self(n-1) + 2*Self(n-2): n in [1..40]]; // Vincenzo Librandi, Oct 18 2012
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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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EXTENSIONS
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STATUS
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approved
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