  The anomalous dimensions of trilinear-quark operators are calculated at
leading twist $t=3$ by diagonalizing the one-gluon exchange kernel of the
renormalization-group type evolution equation for the nucleon distribution
amplitude. This is done within a symmetrized basis of Appell polynomials of
maximum degree $M$ for $M\gg 1$ (up to order 400) by combining analytical and
numerical algorithms. The calculated anomalous dimensions form a degenerate
system, whose upper envelope shows asymptotically logarithmic behavior.
