I saw movie "the man who knew infinity"
In which ramanujan had formulated a formula to calculate number of prime numbers between a range of numbers
My teacher told me that there exist no program which can generate primes
My friend told me that someone had found a counter example of ramanujan'a formula which was billions of billion
So I want to know that did he really formulated the formula, if yes then what is it and how it works (proof required).