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, -1), (0, 1), (1, -1)}.
A151375
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, -1), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =6a(6) =10a(7) =15a(8) =49a(9) =112a(10) =216a(11) =375a(12) =1265a(13) =3069a(14) =6357a(15) =11921a(16) =40845a(17) =102528a(18) =221680a(19) =436203a(20) =1507593a(21) =3869027a(22) =8609811a(23) =17511879a(24) =60844223a(25) =158598846a(26) =360334950a(27) =750899305a(28) =2617859439a(29) =6903200862
External references
- oeis: A151375