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A079194 Number of isomorphism classes of non-associative non-commutative closed binary operations on a set of order n, listed by class size. 5
0, 0, 2, 2, 0, 8, 66, 3115, 0, 1, 14, 18, 270, 467, 48260, 178888824 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Elements per row: 1,1,2,4,8,16,30,... (given by A027423, number of positive divisors of n!)
LINKS
FORMULA
T(n,k) + A079197(n,k) + A079200(n,k) + A079201(n,k) = A079171(n,k).
A079192(n,k) = Sum_{k>=1} T(n,k)*A079210(n,k).
EXAMPLE
Triangle T(n,k) begins:
0;
0;
2, 2;
0, 8, 66, 3115;
0, 1, 14, 18, 270, 467, 48260, 178888824;
...
CROSSREFS
Row sums give A079193.
Sequence in context: A009803 A009615 A184011 * A179198 A117739 A243203
KEYWORD
nonn,tabf,hard,more
AUTHOR
Christian van den Bosch (cjb(AT)cjb.ie), Jan 03 2003
EXTENSIONS
a(0)=0 prepended by Andrew Howroyd, Jan 26 2022
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)