  The moduli space $\mathcal M(r,n)$ of framed torsion free sheaves on the
projective plane with rank $r$ and second Chern class equal to $n$ has the
natural action of the $(r+2)$-dimensional torus. In this paper, we look at the
fixed point set of different one-dimensional subtori in this torus. We prove
that in the homogeneous case the generating series of the numbers of the
irreducible components has a beautiful decomposition into an infinite product.
In the case of odd $r$ these infinite products coincide with certain Virasoro
characters. We also propose a conjecture in a general quasihomogeneous case.
