Minimal encodings of canonical k-mers for general alphabets and even k-mer sizes

To index or compare sequences efficiently, often k-mers, i.e., substrings of fixed length k, are used. For efficient indexing or storage, k-mers are encoded as integers, e.g., applying some bijective mapping between all possible σ^k k-mers and the interval [0,σ^k-1], where σ is the alphabet size.