Universality in Chern-Simons theory

We show that the perturbative part of the partition function in the Chern-Simons theory on a 3-sphere as well as the central charge and expectation value of the unknotted Wilson loop in the adjoint representation can be expressed in terms of the universal Vogel's parameters $\alpha, \beta, \gamma.$ The derivation is based on certain generalisations of the Freudenthal-de Vries strange formula.
Comment: Slightly revised version with minor corrections