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), (1, -1)}.
A151336
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), (1, -1)}.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =1a(4) =2a(5) =0a(6) =5a(7) =26a(8) =28a(9) =42a(10) =369a(11) =908a(12) =1122a(13) =5773a(14) =23119a(15) =42716a(16) =117508a(17) =549438a(18) =1479612a(19) =3367843a(20) =13480787a(21) =46542736a(22) =115686395a(23) =371629486a(24) =1402498101a(25) =4078027887a(26) =11785376915a(27) =42758254550a(28) =140673861443a(29) =410211643221
External references
- oeis: A151336