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), (0, -1), (0, 1), (1, 0), (1, 1)}.
A151372
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), (0, -1), (0, 1), (1, 0), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =3a(3) =4a(4) =26a(5) =80a(6) =387a(7) =1596a(8) =7518a(9) =34656a(10) =167310a(11) =813384a(12) =4040212a(13) =20285408a(14) =103195235a(15) =530042604a(16) =2748206006a(17) =14362312640a(18) =75609109594a(19) =400620871608
External references
- oeis: A151372