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)}.
A151337
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)}.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =1a(4) =2a(5) =1a(6) =11a(7) =27a(8) =60a(9) =216a(10) =724a(11) =1976a(12) =7140a(13) =23723a(14) =78257a(15) =273707a(16) =965000a(17) =3354664a(18) =12105626a(19) =43619606a(20) =158328834a(21) =581558532a(22) =2150453882a(23) =7986765356a(24) =29926146152a(25) =112632743114a(26) =426211686362
External references
- oeis: A151337