2431/2430, the heptacircle comma is a 17-limit superparticular comma of about 0.71 cents. It is the amount by which 1215/512 (layo ninth, a stack consisting of major limma, Pythagorean whole tone and an octave) falls short of a stack consisting of 11/8, 13/8 and 17/16. By tempering it out is defined the heptacircle temperament, which enables the heptacircle chords.
The name heptacircle was named by Xenllium in 2023, for the following reason - it is represented by monzo [-1 -5 -1 0 1 1 1⟩, using a zero value ("circle") in the mediant place of seven variables (17-limit no-seven subgroup comma). It is similar to the pentacircle comma, 896/891 (11-limit no-five subgroup comma).