English

On arithmetic terms expressing the prime-counting function and the n-th prime

Number Theory 2025-08-05 v2

Abstract

We present the first fixed-length elementary closed-form expressions for the prime-counting function, π(n)\pi(n), and the nn-th prime number, p(n)p(n). These expressions are arithmetic terms, requiring only a finite and fixed number of elementary arithmetic operations from the set: addition, subtraction, multiplication, integer division, and exponentiation. Mazzanti proved that every Kalmar function can be represented as an arithmetic term. We develop an arithmetic term representing the prime omega function, ω(n)\omega(n), which counts the number of distinct prime divisors of a positive integer nn. From this term, we find immediately an arithmetic term for the prime-counting function, π(n)\pi(n). Combining these results with a new arithmetic term for binomial coefficients and novel prime-related exponential Diophantine equations, we manage to develop an arithmetic term for the nn-th prime number, p(n)p(n), thereby providing a constructive solution to the fundamental question: Is there an order to the primes?

Keywords

Cite

@article{arxiv.2412.14594,
  title  = {On arithmetic terms expressing the prime-counting function and the n-th prime},
  author = {Mihai Prunescu and Joseph M. Shunia},
  journal= {arXiv preprint arXiv:2412.14594},
  year   = {2025}
}

Comments

Four appendixes with codes and formulas; Revision includes corrections of several typos, including a typo which impacted the monomial expansion for the final p(n) term

R2 v1 2026-06-28T20:41:45.995Z