Permanent of the (0,1)-matrix with ij-th entry equal to zero iff (i=1,j=1),(i=1,j=2),(i=1,j=3),(i=2,j=3),(i=3,j=3),... In other words, the ij-th entry of the matrix is zero iff it is on the path which start from the entry (i=1,j=1) and moves in the matrix alternating 3 steps to the right to 3 steps down.

A098926

Permanent of the (0,1)-matrix with ij-th entry equal to zero iff (i=1,j=1),(i=1,j=2),(i=1,j=3),(i=2,j=3),(i=3,j=3),... In other words, the ij-th entry of the matrix is zero iff it is on the path which start from the entry (i=1,j=1) and moves in the matrix alternating 3 steps to the right to 3 steps down.