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, -1), (-1, 0), (-1, 1), (0, -1), (1, 0), (1, 1)}.
A151369
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, -1), (-1, 0), (-1, 1), (0, -1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =3a(4) =15a(5) =51a(6) =208a(7) =893a(8) =3841a(9) =17564a(10) =80641a(11) =381664a(12) =1829908a(13) =8912028a(14) =43963132a(15) =219194931a(16) =1104020412a(17) =5607960015a(18) =28711787341a(19) =148026751064a(20) =768028849708
External references
- oeis: A151369