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A038058
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Number of labeled trees with 2-colored nodes.
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3
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1, 2, 4, 24, 256, 4000, 82944, 2151296, 67108864, 2448880128, 102400000000, 4829076871168, 253613523861504, 14681377947951104, 928873060356849664, 63772920000000000000, 4722366482869645213696, 375183514207494575620096
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = A038057(n)/n = 2^n * n^(n-2) for n>=1. E.g.f. B(2*x) where B(x) is e.g.f. of A000272.
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MAPLE
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MATHEMATICA
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nn = 17; f[x_] := Sum[n^(n - 2) x^n/n!, {n, 1, nn}];
Range[0, nn]! CoefficientList[Series[f[2 x] + 1, {x, 0, nn}], x] (* Geoffrey Critzer, Nov 02 2014 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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