The aim is to find a recurrence of prime numbers. So we'll take the trigonometric functions as they're standard periodic functions, like $\sin(x)$: we'll take as an argument of $\sin(x)$ the angle found before:
$$y=\sin(πx/n) \mid n ∈ ℕ, n>1.$$
Fixed $n$ the function gives as result 0 exactly when $x=n$ for obvious reasons and the other zeros are given for every k*n, where $k=1,2,3,...$
Then take $n_1 ∈ ℕ, n_1 > 1$, for all $n ≠ n_1$ and $ n_1 ∉ $ set of all zeros of the harmonics, $n_1$ is prime because there is only one harmonic that has the first zero in $x=n_1$. This harmonic is called prime harmonic.
The set of all zeros of prime harmonics are ℕ/{1} then we can build a function that preserves these zeros. The best method is the multiplication. If the first prime harmonic has n=2, the next number without the zero is 3. Then take the second harmonic that has n=3, the next number without zero is 5 and so on. With this method we build gradually a function $p(x)$:
$$p(x) = \prod_{n=2}^\infty \sin (πx/n)$$ where $x, n ∈ ℕ$ for all $n \in \sin (πx/n).$ This function $(p(X))$ is called prime function.