The extended binary quadratic residue code of length 42 holds a 3-design
share
The codewords of weight 10 of the [42,21,10] extended binary quadratic residue code are shown to hold a design of parameters 3-(42,10,18). Its automorphism group is isomorphic to PSL(2,41). Its existence can be explained neither by a transitivity argument, nor by the Assmus-Mattson theorem.
READ FULL TEXT