Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (1, 0)}.
A151255
Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (1, 0)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =3a(4) =8a(5) =15a(6) =39a(7) =77a(8) =216a(9) =459a(10) =1265a(11) =2739a(12) =7842a(13) =17641a(14) =49854a(15) =113175a(16) =327604a(17) =761787a(18) =2182833a(19) =5101595a(20) =14868582a(21) =35338401a(22) =102146176a(23) =243510453a(24) =713019480a(25) =1721265625a(26) =5005198029a(27) =12105626337a(28) =35565979706a(29) =86870058279
External references
- oeis: A151255