This is strange... I can sort of proove this. ( n(1/2 + 1/3 + ... + 1/pa) - (1/3 + 2/5 + ... + (a-1)/pa) minus all whole queries ) <= ½ --> n = p If it's true and I was the first to find the serie; can I name it after me? In that case i would like to name my equation the EO-equation. But pa is the last existing prime between the two numbers 1 and n. Thereby it's a bit difficult to find really big primes, but anyway.