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There are 270,474,142 Nonisomorphic 2(9,4,6) Designs

Patric R. J. Ostergard 1
1 Department of Computer Science and Engineering Helsinki University of Technology P.O. Box 5400 02015 HUT, Finland

Abstract

We enumerate the 2-(9,4,6) designs and find 270,474,142 non-isomorphic such designs in a backtrack search. The sizes of their automorphism groups vary between 1 and 360. Out of these designs, 19,489,464 are simple and 2,148,676 are decomposable.