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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
A151351
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), (-1, 1), (0, 1), (1, -1), (1, 1)}.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =1a(4) =8a(5) =18a(6) =90a(7) =301a(8) =1413a(9) =5628a(10) =26083a(11) =114133a(12) =536065a(13) =2475101a(14) =11844488a(15) =56598072a(16) =275910093a(17) =1350392157a(18) =6692423872a(19) =33348850521a(20) =167631991925a(21) =847255772901
External references
- oeis: A151351