20/19

In 19-limit just intonation, 20/19 is the small undevicesimal semitone, measuring about 88.8¢ (almost exactly 1/3 of a subminor third of 7/6). Its octave complement is 19/10, the "undevicesimal diminished octave". It is very close to 2 steps out of 27edo, or 88.8889 cents.

The small comma (7/6)/(20/19)^3 = 48013/48000 is tempered out in 12, 41, 53, 68, 80, 94, 121, 161, 190, 202, 217, 229, 243, 270, 282, 311, 323, 364, 460, 472, 513, 525, 540, 581, 742, 783, 795, 1012, 1053, 1106, 1308, 1323, 1578, 1848, 1889, and 2320 EDOs, leading to a variety of temperaments in which three semitones make up a subminor third.

The password comma, (256/243)/(20/19) = (19/18)/(135/128) = 1216/1215 is tempered out in 12, 29, 41, 53, 65, 77, 87, 94, 99, 106, 111, 118, 130, 140, 152, 159, 183, 193, 205, 217, 270, 282, 311, 323, 364, 400, 422, 581, and 692 EDOs, leading to a variety of temperaments which identifies small undevicesimal semitone with Pythagorean limma and greater undevicesimal semitone with major limma respectively.

20/19

See also