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A344260
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a(n) is the number of relations from an n-element set into a set of at most n elements.
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1
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1, 3, 21, 585, 69905, 34636833, 69810262081, 567382630219905, 18519084246547628289, 2422583247133816584929793, 1268889750375080065623288448001, 2659754699919401766201267083003561985, 22306191045953951743035482794815064402563073, 748380193317489370459454048174977015562807531282433
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OFFSET
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0,2
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COMMENTS
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Symmetrically, also the number of relations from a set of at most n elements into an n-element set.
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LINKS
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FORMULA
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a(n) = (2^(n+n^2) - 1)/(2^n - 1) for n > 0 and a(0) = 1.
a(n) ~ 2^(n^2).
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MATHEMATICA
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Join[{1}, Table[(2^(n+n^2)-1)/(2^n-1), {n, 13}]]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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