# 17/Historical Note

< 17

## Historical Note on $17$

$17$ was the highest number whose square root was proved irrational by Theodorus of Cyrene.

Plutarch reports that the Pythagoreans had a horror of the number $17$.

That was because it lay half way between $16$ and $18$, which are the areas of rectangles whose areas equal their perimeters.

$17$ seems to be a popular age to write a pop song about:

At Seventeen by Janis Ian
7-Teen by The Regents
Edge of Seventeen by Stevie Nicks

to name but three.