Frequencies of HD 181231 observed with CoRoT (bottom panel) and growth rate and azimuthal order of the modelled frequencies of low degree (ℓ ≤ 2) (top panels) excited in a 5.5 and 6 M_⊙ star with a core overshooting of 0.35 H_p, calculated with the Tohoku code. Colours indicate the parity of the mode: even modes in solid red and odd modes in dashed blue lines. Stellar parameters used in the two models are indicated at the top of each model.