待翻译：Hadamard Matrix of Order 668
AI 服务暂时不可用，以下为来源摘要，待恢复后补全翻译：Hadamard Matrix of Order 668 | Epoch AI Find a Hadamard matrix of order 668. Write your Hadamard matrix to an .npy file (using `numpy.save`) and output the filepath. The matrix must be a square array of +1 and -1 entrie…
AI 服务暂时不可用，以下为来源正文，待恢复后补全翻译。
Hadamard Matrix of Order 668 | Epoch AI Find a Hadamard matrix of order 668. Write your Hadamard matrix to an .npy file (using numpy.save) and output the filepath. The matrix must be a square array of +1 and -1 entries. BibTeX Citation @misc{epoch2026, title={Hadamard Matrix of Order 668}, author={{Epoch AI}}, year={2026}, url={https://epoch.ai/frontiermath/open-problems/hadamard}, note={Accessed: 2026-08-12}} Hadamard Matrix of Order 668 "Hadamard Matrix of Order 668" — a problem from FrontierMath: Open Problems, Epoch AI's benchmark of unsolved research mathematics.