17 squares. No smaller square. I've released the first complete Lean proof of optimality for Bidwell's 1998 packing of 17 squares. Built with @OpenAI Astra + @AnthropicAI Opus 5.5. Thanks to @ManassehA06 & @ojoshe for prior work. github.com/ofitzharding/sq17…

lol here's a lean proof of the optimal packing for 19 squares github.com/ofitzharding/sq19