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, 1)}.
A151267
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, 1)}.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =7a(4) =21a(5) =55a(6) =165a(7) =457a(8) =1371a(9) =3909a(10) =11727a(11) =33993a(12) =101979a(13) =298629a(14) =895887a(15) =2640931a(16) =7922793a(17) =23460851a(18) =70382553a(19) =209078319a(20) =627234957a(21) =1867531435a(22) =5602594305a(23) =16709292259a(24) =50127876777a(25) =149690954499a(26) =449072863497
External references
- oeis: A151267