Generalized higher order spt-functions
  We give a new generalization of the spt-function of G.E. Andrews, namely $\textup{Spt}_j(n)$, and give its combinatorial interpretation in terms of successive lower-Durfee squares. We then generalize the higher order spt-function $\textup{spt}_k(n)$, due to F.G. Garvan, to ${}_j\textup{spt}_{k}(n)$, thus providing a two-fold generalization of $\textup{spt}(n)$, and give its combinatorial interpretation. 
Atul Dixit and Ae Ja Yee
math.NT math.CO