Posted by haifeng on 2025-01-01 11:58:33 last update 2025-01-01 14:32:43 | Answers (0) | 收藏
Euler 的证明
\[ \frac{1}{2}\prod_{p\in PRIMES}\frac{p^2+1}{p^2-1}=\frac{\zeta^2(2)}{2\zeta(4)}=\frac{25}{20}. \]
See [1] P.156.
References:
[1] Richard K. Guy, Unsolved Problems in Number Theory.
