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, 0), (-1, 1), (0, -1), (0, 1), (1, -1)}.
A151347
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, 0), (-1, 1), (0, -1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =8a(6) =19a(7) =65a(8) =177a(9) =611a(10) =1928a(11) =6648a(12) =22928a(13) =80851a(14) =292343a(15) =1063611a(16) =3957406a(17) =14818681a(18) =56339994a(19) =215943994a(20) =836246604a(21) =3265240671a(22) =12848804154a(23) =50936668789a(24) =203235590343a(25) =816070826188
External references
- oeis: A151347