Group construction of covering arrays

A covering array t-CA(n,k,g) is a k x n array on a set of g symbols with the property that in each t x n subarray, every t x I column appears at least once. This paper improves many of the best known upper bounds on n for covering arrays, 2-CA (n, k, g) with g + 1 less than or equal to k less than or equal to 2g, for g = 3(...)12 by a construction which in many of these cases produces a 2-CA (n, k, g) with n = k (g - 1) + 1. The construction is an extension of an algebraic method used by Chateauneuf, Colbourn, and Kreher which uses an array and a group action on the array. (C) 2004 Wiley Periodicals, Inc.