Number of 2n-step walks from (0, 0) to (0, 0) on square lattice with winding number zero around (1/2, 1/2).

A387361

Number of 2n-step walks from (0, 0) to (0, 0) on square lattice with winding number zero around (1/2, 1/2).

Terms

    a(0) =1a(1) =4a(2) =34a(3) =360a(4) =4240a(5) =53184a(6) =695462a(7) =9366968a(8) =128974482a(9) =1806466376a(10) =25649169360a(11) =368251171264

External references