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A360515
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Number of 2-color vertex orderings of the labeled path graph on n vertices in which the number 1 is assigned to a vertex in an even position.
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4
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0, 1, 2, 9, 24, 185, 720, 7217, 35840, 451089, 2741760, 41375609, 297133056, 5232134921, 43356465152, 872492313825, 8193895956480, 185503858236065, 1947095049830400, 48978641359097705, 568206904265277440, 15722400263686662105, 199768581446090883072
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OFFSET
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1,3
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COMMENTS
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Bouwer and Star give a recurrence.
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REFERENCES
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Bouwer, I., and Z. Star. "A question of protocol." The American mathematical monthly 95.2 (1988): 118-121. See E(n).
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LINKS
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FORMULA
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PROG
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(PARI) \\ Needs A360514seq from A360514.
seq(n) = {my(v=A360514seq(n)); vector(#v, n, if(n%2, if(n==1, 0, (n-1)*n*v[n-2]-v[n]), v[n]))} \\ Andrew Howroyd, Feb 27 2023
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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