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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
A151452
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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =9a(4) =35a(5) =123a(6) =495a(7) =1989a(8) =8309a(9) =35051a(10) =151437a(11) =659819a(12) =2913973a(13) =12976939a(14) =58299997a(15) =263670833a(16) =1200259447a(17) =5492958255a(18) =25263912743a(19) =116702563415a(20) =541237283707
External references
- oeis: A151452