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A175882
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Number of groupoids of order n with no identity element.
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1
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1, 0, 12, 19440, 4293918720, 298022460937500000, 10314424627908807366593740800, 256923577502496762167593902921782457650400, 6277101735385253516143083463326608130132905949327651766272, 196627050475552807506414708879663572595247698231546775823411085055396409324160
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OFFSET
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0,3
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LINKS
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FORMULA
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PROG
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(PARI) a(n) = n^(n^2) - n^(((n-1)^2)+1) \\ Andrew Howroyd, Jan 23 2022
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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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a(0)=1 prepended and terms a(7) and beyond from Andrew Howroyd, Jan 23 2022
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STATUS
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approved
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