26/25
26/25 |1 0 -2 0 0 1>
67.9002 cents
In 13-limit Just Intonation, 26/25 appears as the difference between the 26th harmonic and the 25th. Thus it makes the difference between 13/8 and 25/16 (a stack of two 5/4's). It measures about 67.9¢.
See: Gallery of Just Intervals, List of Superparticular Intervals