The Catch Rate in the Hoenn Safari Zone is modified from the Pokémon's Catch Rate by dividing it by 12.75 and rounding down. Throwing a Safari Ball undoes this by multiplying the value by 12.75 rounded down after any Catch factor modifiers, resulting in a slightly changed modified catch rate for all Pokémon. The following values are true if you neither Go Near the Pokémon or feed it any Pokéblocks:
Oddish, Geodude, Goldeen, Magikarp, Hoothoot, Ledyba, Spinarak, Wooper:
255 Modified Catch Rate, 50.28% Capture Odds.
Mareep, Sunkern:
229 Modified Catch Rate, 50.28% Capture Odds.
Pikachu, Psyduck, Doduo, Natu, Marill, Pineco, Snubbull, Shuckle, Remoraid:
178 Modified Catch Rate, 40.96% Capture Odds.
Gloom, Rhyhorn, Teddiursa, Houndour, Phanpy:
114 Modified Catch Rate, 23.42% Capture Odds.
Quagsire:
89 Modified Catch Rate, 19.75% Capture Odds.
Golduck, Xatu, Octillery:
64 Modified Catch Rate, 12.33% Capture Odds.
Seaking, Girafarig, Gligar:
51 Modified Catch Rate, 10.66% Capture Odds.
Dodrio, Pinsir, Aipom, Wobbuffet, Pinsir, Stantler, Miltank:
38 Modified Catch Rate, 8.09% Capture Odds.
The Escape Rate is the same across all Pokémon at an initial 15% chance. Each Pokémon starts with an escape factor of 3, which changes when Going Near or feeding the Pokémon Pokéblocks, though it is programmed to always be between the values of 1-20. A random number from 0-99 is chosen, where if it's less than the escaped factor times 5 (<15), the Pokémon will flee at the end of the turn if it is not captured.
Hoenn Safari Zone - Bulbapedia
