∑π⊆B⁡(r,r,t)π⁢ symmetricq|π|=∏h=1r1-q2⁢h+t-11-q2⁢h-1⁢∏1≤h<j≤r1-q2⁢(h+j+t-1)1-q2⁢(h+j-1).