A266167 Number of isotopism classes of unordered pairs of orthogonal Latin squares.

1, 0, 1, 1, 2, 0, 20, 23362, 1101734942

Offset: 1

Author

Ian Wanless, Dec 22 2015

Keywords

• nonn
• more

Comments

The following operations produce things that are counted as equivalent: simultaneous permutation of the rows or columns of both squares; permutation of the symbols within either square; interchanging the squares.

This sequence is also the number of trisotopism classes of *ordered* pairs of orthogonal Latin squares, where the following operations produce things that are counted as equivalent: simultaneous permutation of the rows or columns of both squares; permutation of the symbols within either square; transposing both squares.

Links

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

Crossrefs

Cf. A072377, A129732, A266166, A266168, A266169.