Number of walks on square lattice that start and end at origin after 2n steps, not touching origin at intermediate stages.
A054474
Number of walks on square lattice that start and end at origin after 2n steps, not touching origin at intermediate stages.
Terms
- a(0) =1a(1) =4a(2) =20a(3) =176a(4) =1876a(5) =22064a(6) =275568a(7) =3584064a(8) =47995476a(9) =657037232a(10) =9150655216a(11) =129214858304
External references
- oeis: A054474