Doubly resolvable designs from generalized Bhaskar Rao designs

Abstract In this paper we construct a resolvable ( k ( k + 1), k , k −1)-BIBD for each k ⩾3, k a prime or prime power. For k ⩾ 5 such a design was previously unknown. In fact, for these parameters we show that there are at least k − 1 nonisomorphic resolutions of the constructed design and that a pair of orthogonal resolutions exist.