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A309294
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(1/2) times the sum of the elements of all subsets of [n] whose sum is divisible by two.
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2
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0, 0, 1, 6, 20, 60, 168, 448, 1152, 2880, 7040, 16896, 39936, 93184, 215040, 491520, 1114112, 2506752, 5603328, 12451840, 27525120, 60555264, 132644864, 289406976, 629145600, 1363148800, 2944401408, 6341787648, 13623099392, 29192355840, 62411243520
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OFFSET
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0,4
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LINKS
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FORMULA
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G.f.: -x^2*(4*x^3-4*x^2+1)/(2*x-1)^3.
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MATHEMATICA
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LinearRecurrence[{6, -12, 8}, {0, 0, 1, 6, 20, 60}, 40] (* Harvey P. Dale, Aug 27 2021 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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