A class of constacyclic codes over a finite field

AbstractLet Fq be a finite field with q=pm elements, where p is an odd prime and m⩾1. In this paper, we explicitly determine all the μ-constacyclic codes of length 2n over Fq, when the order of μ is a power of 2. We further obtain all the self-dual negacyclic codes of length 2n over Fq and give some illustrative examples. All the repeated-root λ-constacyclic codes of length 2nps over Fq are also determined for any nonzero λ in Fq. As examples all the 2-constacyclic, 3-constacyclic codes of length 2n5s over F5 and all the 3-constacyclic, 5-constacyclic codes of length 2n7s over F7 for n⩾1, s⩾1 are derived