36/35
[2 2 -1 -1⟩
48.77038 cents
The septimal quarter tone (ratio: 36/35, size: 48.77038 cents) is the difference between 10/9 and 8/7, 7/6 and 6/5, 5/4 and 9/7, 14/9 and 8/5, 5/3 and 12/7, and 7/4 and 9/5. It has a numerator which is both the sixth square number and the eighth triangular number, leading to it being the product of two superparticular commas both as 64/63 * 81/80 and as 66/65 * 78/77; it is also 45/44 * 176/175, 51/50 * 120/119 and 128/125 * 225/224.