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A292062
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Wiener index of the n-transposition graph.
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2
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0, 1, 21, 552, 19560, 920160, 55974240, 4293596160, 406306575360, 46556342784000, 6357567896064000, 1020650937901056000, 190386526063878144000, 40844355820490686464000, 9987985777548364185600000, 2762125829379285162393600000, 857790151281459139077734400000
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OFFSET
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1,3
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LINKS
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FORMULA
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a(n) = n! * (n*n! - abs(Stirling1(n+1, 2))) / 2.
(End)
a(n) = (n!/2) * Sum_{k=1..n-1} abs(Stirling1(n, n-k))*k. - Andrew Howroyd, Dec 09 2017
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MATHEMATICA
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Table[n! (n n! + (-1)^n StirlingS1[n + 1, 2])/2, {n, 20}]
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PROG
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(PARI)
a(n) = n! * (n*n! - abs(stirling(n+1, 2, 1))) / 2; \\ Andrew Howroyd, Sep 08 2017
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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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