Number of self-avoiding polygons of length 2n on square lattice (not allowing rotations).

A002931

Number of self-avoiding polygons of length 2n on square lattice (not allowing rotations).

Terms

    a(0) =0a(1) =1a(2) =2a(3) =7a(4) =28a(5) =124a(6) =588a(7) =2938a(8) =15268a(9) =81826a(10) =449572a(11) =2521270a(12) =14385376a(13) =83290424a(14) =488384528a(15) =2895432660a(16) =17332874364a(17) =104653427012a(18) =636737003384

External references