I wonder which theorem has the most proofs, or has been proven in the most ways? I know of Loomis' The Pythagorean Proposition which came out decades ago & contains 370 proofs & more, & the proofs are even catalogued into four types (algebraic, geometric, etc). So that makes me think the Pythagorean theorem is the one. What about the infinitude of primes though? Or maybe there's a theorem I haven't thought of?