Cadence numbers can be found in the links below.
page 8: https://archive.stsci.edu/kepler/release_notes/release_notes25/KSCI-19065-002DRN25.pdf
page 7: https://archive.stsci.edu/missions/kepler/docs/drn/release_notes02/DataRelease_02_Notes_2009102213.pdf
Below I list the quarters, channels, cadences, and the total number of cadences for the cluster NGC 6819. Note that there are no data for this cluster in quarters 6, 10, and 14.