cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A040082 Number of inequivalent Latin squares (or isotopy classes of Latin squares) of order n.

Original entry on oeis.org

1, 1, 1, 2, 2, 22, 564, 1676267, 115618721533, 208904371354363006, 12216177315369229261482540
Offset: 1

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Author

Keywords

Comments

Here "isotopy class" means an equivalence class of Latin squares under the operations of row permutation, column permutation and symbol permutation. [Brendan McKay]

References

  • R. A. Fisher and F. Yates, Statistical Tables for Biological, Agricultural and Medical Research. 6th ed., Hafner, NY, 1963, p. 22.
  • J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 210.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A002860, A003090, A000315. See A000528 for another version.

Extensions

7 X 7 and 8 X 8 results confirmed by Brendan McKay
Beware: erroneous versions of this sequence can be found in the literature!
a(9)-a(10) (from the McKay-Meynert-Myrvold article) from Richard Bean, Feb 17 2004
a(11) from Petteri Kaski (petteri.kaski(AT)cs.helsinki.fi), Sep 18 2009

A000479 Number of 1-factorizations of K_{n,n}.

Original entry on oeis.org

1, 1, 1, 2, 24, 1344, 1128960, 12198297600, 2697818265354240, 15224734061278915461120, 2750892211809148994633229926400, 19464657391668924966616671344752852992000
Offset: 0

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Author

Keywords

Comments

Also, number of Latin squares of order n with first row 1,2,...,n.
Also number of fixed diagonal Latin squares of order n. - Eric W. Weisstein, Dec 18 2005
Also maximum number of Latin squares of order n such that no two of them have all the same rows (respectively, columns). - Rick L. Shepherd, Mar 01 2008

References

  • CRC Handbook of Combinatorial Designs, 1996, p. 660.
  • Denes and Keedwell, Latin Squares and Applications, Academic Press 1974.

Crossrefs

See A040082 and A264603 for other versions.

Formula

a(n) = A000315(n)*(n-1)! = A002860(n)/n!.

Extensions

a(11) (from the McKay-Wanless article) from Richard Bean, Feb 17 2004
Showing 1-2 of 2 results.