A covering array t-CAðn; k; gÞ is a k n array on a set of g symbols with the property that in each t n subarray, every t 1 column appears at least once. This paper improves many of the best known upper bounds on n for covering arrays, 2-CAðn; k; gÞ with gþ 1 k 2g, for g 1⁄4 3 12 by a construction which in many of these cases produces a 2-CAðn; k; gÞ with n 1⁄4 kðg 1Þ þ 1. The construction is an...

‎in [u‎. ‎dempwolff‎, ‎on extensions of elementary abelian groups of order $2^{5}$ by $gl(5,2)$‎, ‎textit{rend‎. ‎sem‎. ‎mat‎. ‎univ‎. ‎padova}‎, ‎textbf{48} (1972)‎, ‎359‎ - ‎364.] dempwolff proved the existence of a group of the‎ ‎form $2^{5}{^{cdot}}gl(5,2)$ (a non split extension of the‎ ‎elementary abelian group $2^{5}$ by the general linear group‎ ‎$gl(5,2)$)‎. ‎this group is the second l...