On orthogonal designs in order 48

On Full Orthogonal Designs in Order 56

We find new full orthogonal designs in order 56 and show that of 1285 possible OD(56; s1, s2, s3, 56—s1—s2-s3) 163 are known, of 261 possible OD(56; s1, s2, 56—s1—s2) 179 are known. All possible OD(56; s1, 56 — s1) are known. Keywords : Construction, sequences, circulant matrices, amicable sets, orthogonal designs, AMS Subject Classification: Primary 05B15, 05B20, Secondary 62K05. Publication D...

On amicable orthogonal designs of order 8

Some new amicable orthogonal designs of order 8 are found as part of a complete search of the equivalence classes for orthogonal designs OD(8; 1, 1, 1, 1), OD(8; 1, 1, 1, 4), OD(8; 1, 1, 2, 2), OD(8; 1, 1, 1, 2), OD (8; 1, 1, 2, 4), OD(8; 1, 1, 1, 3), OD(8; 1, 1, 2, 3), OD(8; 1, 1, 1, 5) and OD(8; 1, 1, 3, 3). 2000 Mathematics subject classification (Amer. Math. Soc.): 05B30, 15A36.

Three variable full orthogonal designs of order 56

Using the doubling lemma, amicable sets of eight circulant matrices and four complementary negacyclic matrices, we show that all full triples are types of orthogonal designs of order 56. This implies that all full orthogonal designs OD(2t7;x, y, 2t7− x− y) exist for any t ≥ 3.

Orthogonal designs of order 32 and 64 via computational algebra

All triples for orthogonal designs of order 40

The use of amicable sets of eight circulant matrices and four negacyclic matrices to generate orthogonal designs is relatively new. We find all 1841 possible orthogonal designs of order 40 in three variables, using only these new techniques.