Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0), and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)}.
A172361
Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0), and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =3a(3) =6a(4) =38a(5) =160a(6) =905a(7) =4830a(8) =28308a(9) =166992a(10) =1024758a(11) =6389460a(12) =40724244a(13) =263385408a(14) =1728855843a(15) =11484066594a(16) =77130790880a(17) =523010474272
External references
- oeis: A172361