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A023813
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a(n) = n^(n*(n+1)/2).
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13
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1, 1, 8, 729, 1048576, 30517578125, 21936950640377856, 459986536544739960976801, 324518553658426726783156020576256, 8727963568087712425891397479476727340041449, 10000000000000000000000000000000000000000000000000000000
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OFFSET
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0,3
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COMMENTS
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Determinant of n X n matrix M_(i,j) = binomial(n*i,j). - Benoit Cloitre, Sep 13 2003
Number of commutative binary operations on an n-set. Labeled commutative groupoids.
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LINKS
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FORMULA
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MAPLE
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MATHEMATICA
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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Lyle Ramshaw (ramshaw(AT)pa.dec.com)
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EXTENSIONS
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STATUS
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approved
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