Number of n-step walks on a square lattice starting from the origin but not returning to it at any stage.
A063887
Number of n-step walks on a square lattice starting from the origin but not returning to it at any stage.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =48a(4) =172a(5) =688a(6) =2576a(7) =10304a(8) =39340a(9) =157360a(10) =607376a(11) =2429504a(12) =9442448a(13) =37769792a(14) =147495104a(15) =589980416a(16) =2311926188a(17) =9247704752a(18) =36333781776a(19) =145335127104a(20) =572189853200
External references
- oeis: A063887