Latin rectangle

Latin rectangle

[′lat·ən ′rek‚taŋ·gəl]
(mathematics)
An r × n matrix, with n equal to or greater than r in which each row is a permutation of the numbers 1, 2, …, n, and no number appears in a column more than once.
References in periodicals archive ?
I don't know if there is any reasonable expression for the number of three-rowed Latin rectangles on n symbols, where the top row is normalized to 1,2,3 .