  In this note we prove an integral formula for the bare one-leg PT vertex with
descendents.
  The formula follows from the PT version of Ellingsrud-G\"ottsche-Lehn formula
that is explained here. We apply the integral formula to obtain an elementary
proof of rationality of one-leg capped PT vertex with descendents.
  We also obtain an integral formula for degree zero DT invariants with
descendents. Finally we propose an explicit non-equivariant DT/PT
correspondence as well as one descendent insertion fully-equivariant DT/PT
formula.
