That can be simplified to the level of illumination of Io and Ganymede as seen from Triton, accounting for all eclipses (probably not literally, but there are natural phenomena which produce patterns at least as interesting; see pulsars).

Since it's more likely that a natural phenomenon created this pattern of observations than that positional notation and time-ordering are shared by a given ETI, I would observe and try to understand the natural system which created this pattern.