Group divisible designs with block size four and type $g^u{b}^1(gu/2{)}^1$

Anthony D. Forbes

We discuss group divisible designs with block size four and type $g^u{b}^1(gu/2{)}^1$, where $u=5$, 6 and 7. For integers $a$ and $b$, we prove the following. (i) A 4-GDD of type $…