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), (-1, 0), (0, -1), (0, 1), (1, -1), (1, 0)}.
A151472
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), (-1, 0), (0, -1), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =9a(4) =30a(5) =110a(6) =423a(7) =1687a(8) =6984a(9) =29574a(10) =128074a(11) =564652a(12) =2527292a(13) =11463972a(14) =52602015a(15) =243824807a(16) =1140448152a(17) =5377337150a(18) =25539196048a(19) =122093592944a(20) =587170555168
External references
- oeis: A151472