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The '''400 equal divisions of the octave''' ('''400edo''') is the [[EDO|equal division of the octave]] into 400 parts of exact 3 [[cent]]s each. 400edo is consistent in the [[21-odd-limit]]. It tempers out the unidecma, {{monzo| -7 22 -12 }}, and the qintosec comma, {{monzo| 47 -15 -10 }}, in the 5-limit; [[2401/2400]], 1959552/1953125, and 14348907/14336000 in the 7-limit; 5632/5625, [[9801/9800]], 117649/117612, and [[131072/130977]] in the 11-limit; [[676/675]], [[1001/1000]], [[1716/1715]], [[2080/2079]], [[4096/4095]], [[4225/4224]] and 39366/39325 in the 13-limit, supporting the [[decoid]] temperament and the [[quinmite]] temperament.
The '''400 equal divisions of the octave''' ('''400edo''') is the [[EDO|equal division of the octave]] into 400 parts of exact 3 [[cent]]s each.  


400edo doubles [[200edo]], which holds a record for the best 3/2 fifth approximation. 400 is also the number of years in the Gregorian calendar's leap cycle. 400edo supports the Sym454 calendar scale with 231\400 as the generator, which can be treated as 1/3 syntonic comma meantone.  
== Theory ==
400edo is consistent in the [[21-odd-limit]]. It tempers out the unidecma, {{monzo| -7 22 -12 }}, and the qintosec comma, {{monzo| 47 -15 -10 }}, in the 5-limit; [[2401/2400]], 1959552/1953125, and 14348907/14336000 in the 7-limit; 5632/5625, [[9801/9800]], 117649/117612, and [[131072/130977]] in the 11-limit; [[676/675]], [[1001/1000]], [[1716/1715]], [[2080/2079]], [[4096/4095]], [[4225/4224]] and 39366/39325 in the 13-limit, supporting the [[decoid]] temperament and the [[quinmite]] temperament.
 
400edo doubles [[200edo]], which holds a record for the best 3/2 fifth approximation. 400 is also the number of years in the Gregorian calendar's leap cycle. 400edo supports the Sym454 calendar scale with 231\400 as the generator, which can be treated as 2/5 syntonic comma meantone.  


=== Prime harmonics ===
=== Prime harmonics ===
{{Primes in edo|400}}
{{Primes in edo|400}}
=== Table of intervals ===
{| class="wikitable"
|+
!Step
!Name
!Associated ratio
!Notes
|-
|0
|unison
|1/1 exact
|
|-
|35
|septendecimal semitone
|[[17/16]]
|
|-
|231
|Gregorian leap week fifth
|118/79
|
|-
|234
|perfect fifth
|[[3/2]]
|
|-
|400
|octave
|1/1 exact
|
|}


== Scales ==
== Scales ==