According to mathworld 41,42. "Derivatives $\zeta^{(n)}(1/2)$ can also be given in closed form" with example for the first derivative.

What is the closed form? References?

The motivation is that this question expresses $\zeta(3)$ in terms of $\zeta(1/2)$ and the first 3 derivatives, so closed form possibly might result in closed form for zeta(3) (unless the closed form is derived by the linked question).

Particaluraly intersted in the second and third derivatives.

On what the derivatives would depend helps too.