The Pirate Game

Level 6●●●●● Expert~10 min

Problem

Five rational pirates (ranked 55 = most senior down to 11) split 100100 gold coins. The most senior proposes a division; all pirates (including the proposer) vote. If at least half approve, it passes; otherwise the proposer is thrown overboard and the next-most-senior proposes. Each pirate's priorities, in order: (1) survive, (2) maximize gold, (3) all else equal, prefer to throw a pirate overboard. What does pirate 55 propose?