Does anyone have the formula for odds of invasion?

yes..........

total invasion attack = ......well there's so much that i have to use a spreadsheet to calculate it
total invasion defense = normal planet attack + normal planet defense + invasion-only planet defense
don't forget buffs, debuffs, and legion bonuses (note: legion bonus also applies to invasion-only planet defense)

invasion chance = total invasion attack calculated properly / (3 * total invasion defense calculated properly)

(your attack/3)/total planet attack, defense and invasion defense.

i believe it is .6 times planet attack?

The formula has a cap also - minimum 10% chance of failure, even if the planet has zero defence.

No, it's not.

Revis... you can believe what you want... doesn't make it correct though

planet attack and planet defense and invasion-only defense are weighted equally... keep in mind the planet may have been buffed debuffed, which those buffs and debuffs will have to be applied properly if you're manually calculating from the values on the buildings themselves

if the planet has been affected by an orbital mass disruptor, the planet's attack has been lowered to 0.7 of the original amount
if the planet has been affected by an ion storm charge, the planet's defense has been lowered to 0.85 of the original amount
not sure if invasion-only defense is affected by ion storm charge
(too lazy to list all the buffs)

also don't forget to apply the legion bonus to planet attack, planet defense, AND invasion-only defense

just thought id heard it around somewhere. ill take your word for it that i was wrong

They mentioned that in the post, and realized they simply miscalculated and the equal-weighting is correct.