13/10
13/10 |-1 0 -1 0 0 1>
454.21395 cents
File:Jid 13 10 pluck adu dr220.mp3 sound sample
In 13-limit Just Intonation, 13/10 is an interseptimal interval measuring about 454.2¢. It falls in an ambiguous zone between a wide major third such as 9/7 and a flat perfect fourth such as 21/16. The descriptor "interseptimal" comes from Margo Schulter, and indicates its position between those two septimal (7-based) extremes. 13/10 appears between the 10th and 13th overtones of the harmonic series and appears in such chords as 8:10:13, a quasi-augmented triad. 13/10 also appears in the relatively-simple 10:13:15 triad, which consists of an interseptimal ultramajor third (13/10) and an interseptimal inframinor third (15/13) which stack to make a 3/2 perfect fifth. It is well-approximated in 24edo, 29edo, 37edo, and of course, infinitely many other EDO systems.
See: Gallery of Just Intervals, List of root-3rd-P5 triads in JI