In this [article][1], Takaaki Musha proves that $\zeta(2n+1) \notin (2\pi )^{2n+1} \mathbb{Q}$. I haven't read it so I can't say more. See this [question][2]. [1]: http://www.zentralblatt-math.org/zmath/en/advanced/?q=an%3Apre05770900&format=complete [2]: http://mathoverflow.net/questions/38190/values-of-zeta-at-odd-positive-integers-and-borels-computations