65/19 atom
Interval information |
272629233/272629760, the 65/19 atom, is an unnoticeable comma in the 2.3.5.13.19 subgroup. It is the amount by which the 13-comma 6656/6561 ("tetris comma") exceeds the 19/5-comma 41553/40960 (an apotome above 19/16 lowered by 5/4). Their difference is small enough that sagittal accidentals equate the 13-comma with the 19/5 comma: the most accurate possible representation of the 13th harmonic in sagittal accidentals (as three octaves above a )/||| P5
) accrues this 0.0033 ¢ error.
Alternatively, the 65/19 atom is the difference between the pythagorean comma 312/219 raised by 513/512 and the wilsorma 65/64.