A129732 Number of main classes of Graeco-Latin squares of order n. That is, species of pairs of orthogonal Latin squares.

1, 1, 1, 0, 7, 2165, 91846374

Offset

3,5

Links

Table of n, a(n) for n=3..9.

J. Egan and I. M. Wanless, Enumeration of MOLS of small order, Mathematics of Computation 85, 2016, 799-824.

B. D. McKay, Latin squares.

I. Wanless, Data on mutually orthogonal Latin squares (MOLS).

Example

The unique example for n=3 has two Latin squares [[0, 2, 1], [2, 1, 0], [1, 0, 2]] and [[0, 2, 1], [1, 0, 2], [2, 1, 0]].

Crossrefs

Cf. A003090, A266166, A266167, A266168, A266169, A266170, A266171, A266172, A266173.

Sequence in context: A139299 A004818 A125538 * A186164 A203686 A248142

Adjacent sequences: A129729 A129730 A129731 * A129733 A129734 A129735

Keyword

hard,more,nice,nonn

Author

Brendan McKay, May 13 2007

Extensions

a(9) by Egan and Wanless added by Janne I. Kokkala, Sep 08 2015

Status

approved