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A099121
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Number of orbits of the wreath product of S_n with S_n on n X n matrices over {0,1,2}.
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12
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1, 3, 21, 220, 3060, 53130, 1107568, 26978328, 752538150, 23667689815, 828931106355, 32006008361808, 1350990969850340, 61902409203193230, 3060335715568296000, 162392216278033616560, 9206887338937200407418
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OFFSET
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0,2
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COMMENTS
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This is the number of possible votes of n referees judging n dancers by a mark between 0 and 2, where the referees cannot be distinguished.
a(n) is the number of n element multisets of n element multisets of a 3-set. - Andrew Howroyd, Jan 17 2020
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LINKS
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FORMULA
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a(n) = binomial( (n+1)*(n+2)/2 + n-1, n).
a(n) = binomial(binomial(n + 2, n) + n - 1, n). - Andrew Howroyd, Jan 17 2020
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PROG
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(PARI) a(n)={binomial(binomial(n + 2, n) + n - 1, n)} \\ Andrew Howroyd, Jan 17 2020
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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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