New Formulas for Semi-Primes. Testing, Counting and Identification of the $n^{th}$ and next Semi-Primes

Issam Kaddoura, Samih Abdul-Nabi, Khadija Al-Akhrass

In this paper we give a new semiprimality test and we construct a new formula for ${\pi }^{(2)}(N)$, the function that counts the number of semiprimes not exceeding a given number $N$.…