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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

Table of n, a(n) for n=0..8.

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.)