the asymptotic limit of the number of terms of the Farey sequence

It is about 0.3 times the square of n.

Here is the link to the Wolfram MathWorld article on this.

keywords:

[Mathematics]

[Number Theory]

[fractions]

[set of irreducible rational numbers]

[arranged in increasing order]

[middle term is always 1/2]

[equivalent statements]

[inferential equivalence]

[totient function]