Number of self-intersecting walks of length n on a square lattice such that at each point the angle turns 90 degrees.

A293865

Number of self-intersecting walks of length n on a square lattice such that at each point the angle turns 90 degrees.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =2a(6) =3a(7) =5a(8) =8a(9) =13a(10) =21a(11) =37a(12) =56a(13) =90a(14) =144a(15) =239a(16) =374a(17) =592a(18) =948a(19) =1558a(20) =2431a(21) =3848a(22) =6127a(23) =9972a(24) =15602a(25) =24658a(26) =39158a(27) =63265a(28) =99110a(29) =156505

External references