Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 0), (0, -1), (0, 1), (1, -1), (1, 1)}.
A151473
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (-1, 0), (0, -1), (0, 1), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =12a(4) =49a(5) =198a(6) =863a(7) =3884a(8) =17975a(9) =85334a(10) =412190a(11) =2024852a(12) =10077117a(13) =50742026a(14) =258072225a(15) =1324122267a(16) =6846977215a(17) =35650800062a(18) =186783189059a(19) =984088270530
External references
- oeis: A151473