#### Abstract

It is known that if there are base sequences of lengths m + p, m + p, m, m and y is a Yang number then there are T-sequences of length (2m + p)y.

Let G = {g : g = 2^{a}10^{b}26^{c}, a, b, c non negative integers}. We show that base sequences currently exist for p = 1 and m ∑{I, ... , 18,20,21,23,25, 29} U G. Yang numbers currently exist for y ∑ {3, 5, ... ,33,37,41,45,51,53,59,65,81, ... and 2g + 1 > 81, g ∑ G}. This means T-sequences exist for

0_{1 }= {t : t odd ≤ 59} U {s : 63 ≤ s ≤ 199,s not prime, s ≠ 183}

0_{2} = {ym : y a Yang number, m a base sequence}

0_{3} = {g + g' : g,g'∑ G(e.g. we may take g' = 1)}

E_{1} = {2yp : y a Yang number and p ∑ 0_{1} U 0_{2} U 0_{3} U E_{1}. In particular we find a new SBIBD(4k^{2}, 2k^{2} + k, k^{2} + k) for k = 43, and new Hadamard matrices with maximum known excess for n = 860 and 1204.

## Publication Details

Christos Koukouvinos and Jennifer Seberry, Addendum to further results on base sequences, disjoint complementary sequences, OD(4t; t, t, t, t) and the excess of Hadamard matrices, Twenty-Second Southeastern Conference on Combinatorics, Graph Theory and Computing, and Congressus Numerantium, 82, (1991), 97-103.