This paper explores the use of a double-base number system (DBNS) in constant integer multiplication. The DBNS recoding technique represents constants in a multiple-radix way in the hopes of minimizing computation during constant multiplication. The paper presents a proof to show that multiple-radix representation diminishes the number of additions in a sublinear way. We prove Lefevre's conjecture that the multiplication by an integer constant is achievable in sublinear time. The proof is based on some interesting properties of the double-base number system. The paper provides numerical data showcasing some of the most recent results.