A note on Romanov's constant

Summary

In 1934 Romanov showed that a positive proportion of the natural numbers can be written as the sum of a prime and a power of two. Yong-Gao Chen and Xue-Gong Sun proved recently that the lower asymptotic density of this set is larger than 0.0868. We improve this bound to 0.09368 and show various connections with the generalized twin prime problem and the Goldbach-Linnik problem.