文摘
A set of non-negative integers A is an additive 2-basis with range n , if its sumset A+AA+A contains 0,1,…,n0,1,…,n but not n+1n+1. Explicit bases are known with arbitrarily large size |A|=k|A|=k and n/k2≥2/7>0.2857n/k2≥2/7>0.2857. We present a more general construction and improve the lower bound to 85/294>0.289185/294>0.2891.