Number of n-step walks on cubic lattice starting at (0,0,0), ending at (0,floor(n/2),ceiling(n/2)), remaining in the first (nonnegative) octant and using steps (0,0,1), (0,1,0), (1,0,0), (-1,1,1), (1,-1,1), and (1,1,-1).
A328280
Number of n-step walks on cubic lattice starting at (0,0,0), ending at (0,floor(n/2),ceiling(n/2)), remaining in the first (nonnegative) octant and using steps (0,0,1), (0,1,0), (1,0,0), (-1,1,1), (1,-1,1), and (1,1,-1).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =7a(4) =26a(5) =82a(6) =343a(7) =1257a(8) =5594a(9) =22411a(10) =103730a(11) =440350a(12) =2094028a(13) =9255877a(14) =44889351a(15) =204385719a(16) =1006126370a(17) =4685719954a(18) =23337166962a(19) =110633755459a(20) =556199376622
External references
- oeis: A328280