Mathematical Explorations

Interactive visualizations and investigations in number theory and discrete structures.

OEIS A394209: Prime Interval Count

A custom integer sequence counting primes in half-open ternary intervals.

Number Theory

The n-th term is defined as the number of primes in the half-open interval [3^(n-1), 3^n) for n > 0. This sequence has been registered in the OEIS (Online Encyclopedia of Integer Sequences).

Select Term (n)n = 3

Interval: [9, 27)

Primes Count: a(3) = 5

Open A394209 in OEIS →

Growth log-scale (bars represent log10 of counts):

Primes in [9, 27) :