"I have discovered a truly remarkable proof of this theorem which this margin is too small to contain." I can't formulate proper google search query, but I onc

"I have discovered a truly remarkable proof of this theorem which this margin is too small to contain." I can't formulate proper google search query, but I once read funny story where spies were planting a papers with a math problem like it written by a kid, very simple looking, but the answer had actually crazy numbers.