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, 0), (0, -1), (0, 1), (1, -1), (1, 0)}.
A151454
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, 0), (0, -1), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =7a(4) =23a(5) =70a(6) =244a(7) =841a(8) =3070a(9) =11321a(10) =42892a(11) =164826a(12) =643171a(13) =2541709a(14) =10150613a(15) =40950489a(16) =166560231a(17) =682877583a(18) =2818508803a(19) =11707406237a(20) =48902588515a(21) =205338043520a(22) =866285629022
External references
- oeis: A151454