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A038036
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Number of nonisomorphic and nonantiisomorphic rings with n elements.
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1
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1, 2, 2, 10, 2, 4, 2, 46, 10, 4, 2, 20, 2, 4, 4, 316, 2, 20, 2, 20, 4, 4, 2, 92, 10, 4, 53, 20, 2, 8, 2
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OFFSET
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1,2
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COMMENTS
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Number of rings of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the * operator). - Jianing Song, Oct 26 2019
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LINKS
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Table of n, a(n) for n=1..31.
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FORMULA
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a(n) = (A027623(n)+A037290(n))/2. - Jianing Song, Oct 26 2019
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CROSSREFS
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Cf. A027623, A037290.
Sequence in context: A019514 A135816 A157341 * A297793 A319880 A133631
Adjacent sequences: A038033 A038034 A038035 * A038037 A038038 A038039
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KEYWORD
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nonn,hard,more
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AUTHOR
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Christian G. Bower, Jun 15 1998
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EXTENSIONS
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a(16)-a(31) added by Jianing Song, Oct 26 2019
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STATUS
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approved
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