Some $3$-designs invariant under $2.P\hat{I}\pounds L(2,49).$

Minjia Shi, Ruowen Liu, Patrick Solé

We construct a ternary [49,25,7] code from the row span of a Jacobsthal matrix. It is equivalent to a Generalized Quadratic Residue (GQR) code in the sense of van Lint and MacWilli…