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, 1), (0, 1), (1, -1), (1, 0)}.
A151340
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, 1), (0, 1), (1, -1), (1, 0)}.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =2a(4) =4a(5) =8a(6) =28a(7) =108a(8) =372a(9) =1280a(10) =4776a(11) =18464a(12) =71840a(13) =282856a(14) =1134696a(15) =4623328a(16) =19044552a(17) =79217024a(18) =332678424a(19) =1409411128a(20) =6017276432a(21) =25869106896a(22) =111931476168a(23) =487189405200
External references
- oeis: A151340