Sum m from 1 to 2n-1 of sin(π m²/2n)/sin(π m/2n)

Notes:

Finite trigonometric sum
Argument of sine is proportional to the square of the index of the sum

For positive integer n:
Sum m from 1 to 2n-1 of sin(π m^2/2n)/sin(π m/2n) = n

Gaussian