In mathematics, the Landau–Ramanujan constant occurs in a number theory result stating that the number of positive integers less than x that are the sum of two square numbers, for large x, varies as
The constant of proportionality is the Landau–Ramanujan constant, which was discovered independently by Edmund Landau and Srinivasa Ramanujan.
More formally, if N(x) is the number of positive integers less than x which are the sum of two squares, then