On the (v,5,λ)-Family of Bhaskar Rao Designs

G. R. Chaudhry, University of Wollongong
M. Greig, Greig Consulting, Vancouver, Canada
J. Seberry, University of Wollongong

Article comments

This article was originally published as Chaudhry, GR, Grieg, M and Seberry, J, On the (v,5,λ)-Family of Bhaskar Rao Designs, Journal of Statistical Planning and Inference, 106, 2002, 303-327.

Abstract

We establish that the necessary conditions for the existence of Bhaskar Rao designs of block size five are : i). λ(v - 1) ≡ 0 (mod 4) ii). λv(v - 1) ≡ 0 (mod 40) iii). 2|λ. We show these conditions are sufficient: for λ = 4 if v > 215, with 10 smaller possible exceptions and one definite exception at v = 5; for λ = 10 if v > 445, with 11 smaller possible exceptions, and one definite exception at v = 5; and for λ = 20, with the possible exception of v = 32; we also give a few results for other values of λ.