Let$\textrm {S}(n,t,k)$be the maximum size of a code containing only vectors of the kth shell of the integer lattice$\mathbb {Z}^{n}$such that the inner product between distinct vectors does not exceed t. In this paper we compute lower bounds for$\textrm {S}(n,t,k)$for small values of n, t and k by carrying out computer searches for codes with prescribed automorphisms. We prescribe groups of signed permutation automorphisms acting transitively on the pairs of coordinates and coordinate values as well as other closely related groups of automorphisms. Several of the constructed codes lead to improved lower bounds for spherical codes.

Abstract Line systems passing through the origin of the d-dimensional Euclidean space admitting exactly two distinct angles are called biangular. It is shown that the maximum cardinality of biangular lines is at least $$2(d-1)(d-2)$$ 2 ( d - 1 ) ( d - 2 ) , and this result is sharp for $$d\in \{4,5,6\}$$ d ∈ { 4 , 5 , 6 } . Connections to binary codes, few-distance sets, and association schemes are explored, along with their multiangular generalization.