A horizontal park is in the shape of a triangle \( OAB \) with \( AB = 16 \). A vertical lamps post \( OP \) is erected at the point \( O \) such that \( \angle PAO = \angle PBO = 15^\circ \) and \( \angle PCO = 45^\circ \), where \( C \) is the midpoint of \( AB \). Then \( (OP)^2 \) is equal to:
