21/13
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Ratio
21/13
Factorization
3 × 7 × 13-1
Monzo
[0 1 0 1 0 -1⟩
Size in cents
830.2532¢
Name
tridecimal supraminor sixth
Color name
thuzo 6th, 3uz6
FJS name
[math]\text{M6}^{7}_{13}[/math]
Special properties
reduced
Tenney height (log2 nd)
8.09276
Weil height (log2 max(n, d))
8.78463
Wilson height (sopfr(nd))
23
Harmonic entropy
(Shannon, [math]\sqrt{nd}[/math])
~4.2186 bits
[sound info]
open this interval in xen-calc
| Interval information |
(Shannon, [math]\sqrt{nd}[/math])
[sound info]
21/13, the tridecimal supraminor sixth, is ca. 830 cents in size. It has a very good approximation in 13edo.
This interval is a ratio of two consecutive Fibonacci numbers, therefore it approximates the golden ratio, specifically acoustic phi. In this case, 21/13 is ~2.8 ¢ flat of the golden ratio.