The Fraction of Primes

A prime number is a number which is not devisible by any numbers except for one and itself.

I just did a curve fit for the fraction of prime numbers less than or equal to a given number and found a reasonably good fit shown in the plot below. This is probably not a new result since I once saw something similar for a bound on the number of primes. It is just the empirical fit that I found. The fraction of primes is the solid line and the fit the dotted line.