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A055315
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Number of labeled trees with n nodes and 3 leaves.
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2
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4, 60, 720, 8400, 100800, 1270080, 16934400, 239500800, 3592512000, 57081024000, 958961203200, 16999766784000, 317328979968000, 6224529991680000, 128047474114560000, 2757288942600192000, 62039001208504320000, 1456091851893719040000, 35593356379624243200000
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OFFSET
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4,1
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LINKS
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FORMULA
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MAPLE
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a:=n->sum((n-j)*n!/3!, j=3..n): seq(a(n), n=4..19); # Zerinvary Lajos, Apr 29 2007
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MATHEMATICA
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PROG
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(Magma) [Factorial(n)*(n-3)*(n-2)/12: n in [4..25]]; // Vincenzo Librandi, Jul 25 2014
(PARI) for(n=4, 30, print1(n!*(n-3)*(n-2)/12, ", ")) \\ G. C. Greubel, Feb 07 2018
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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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