The Jupiter Effect Book
The inner planets are not resonance orbits with each other,  this means that the ratio Earth-year:Martian-year is irrational. And the exact postions of the planets don't recur.
The positions do approximately recur, but the time between approximate recurrences depends on how accurate you want the recurrence to be.  &quot;accurate to 90 degrees?&quot;  &quot;15 degrees?&quot;  &quot;1 degree?&quot;  Are you only counting right-ascension, or are you also looking at the declension too (the planets don't orbit in exactly the same plane)  Are you willing to make Keplarian approximations, or do you want to include perturbations.
The motions of the planets are simple enough physics, but not simple ratios.  So predicting a &quot;recurrence to a particular accuracy&quot; needs physics to forecast.