Regular diatonic tuning

12-tone Playⓘ, 72-tone (Maneri-Sims notation) Playⓘ, and also (both written the same as 12-tone in Easley Blackwood notation) 17-tone Playⓘ and 19-tone Playⓘ regular diatonic scales
T and S in various equal temperaments (*5-tone and 7-tone are the limits of and not regular diatonic tunings) Play 53ⓘ and Play 31ⓘ

A regular diatonic tuning is any musical scale consisting of "tones" (T) and "semitones" (S) arranged in any rotation of the sequence TTSTTTS which adds up to the octave with all the T's being the same size and all the S's the being the same size, with the 'S's being smaller than the 'T's. In such a tuning, then the notes are connected together in a chain of seven fifths, all the same size (TTTS or a permutation of that) which makes it a Linear temperament with the tempered fifth as a generator.