We study plane partitions satisfying condition an+1,m+1= 0 (this condition is called “pit”) and asymptotic conditions along three coordinate axes. We find the formulas for generating function of such plane partitions. Such plane partitions label the basis vectors in certain representations of quantum toroidal gl1 algebra, therefore our formulas can be interpreted as the characters of these representations. The resulting formulas resemble formulas for characters of tensor representations of Lie superalgebra glm|n. We discuss representation theoretic interpretation of our formulas using q-deformed W-algebra glm|n.
