There is no such formula to find prime numbers because Prime numbers never follow any specific pattern but there are some formulas that are true for prime numbers.  1. x^{2}+x+41 is Prime, where x\\in{W} or x={0,1,2,3,4...} 2. 2^{n}-1, where n is also a prime number is called a Mersenne Prime. This formula is true in 99% of cases means not true for all prime values of n. Example: For n=11, 2^{n}-1=2047 (It is divisible by 23)