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 A328746 Number of loops of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator). 0
 0, 1, 1, 1, 2, 5, 72, 12151, 53146457 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS FORMULA a(n) = (A057771(n)+A057996(n))/2. CROSSREFS For the number of group-like algebraic structures of order n, see: Semigroups: A027851 or A001423 (commutative: A001426); Monoids: A058129 or A058133 (commutative: A058131); Quasigroups: A057991 or A058171 (commutative: A057992); Loops: A057771 or this sequence (commutative: A089925); Groups: A000001 (commutative: A000688); Rings: A027623 or A038036 (commutative: A037289); Rings with unity: A037291; Fields: A069513. Sequence in context: A309366 A007506 A042693 * A172037 A301993 A128297 Adjacent sequences:  A328743 A328744 A328745 * A328747 A328748 A328749 KEYWORD nonn,hard,more AUTHOR Jianing Song, Oct 26 2019 STATUS approved

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Last modified April 12 12:39 EDT 2021. Contains 342920 sequences. (Running on oeis4.)