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, 0), (0, 1), (1, -1)}.
A151259
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, 0), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =35a(6) =104a(7) =309a(8) =950a(9) =3001a(10) =9580a(11) =31122a(12) =102447a(13) =340154a(14) =1141687a(15) =3861440a(16) =13151163a(17) =45099030a(18) =155500732a(19) =538992037a(20) =1877191730a(21) =6565129272a(22) =23052066243a(23) =81232416035a(24) =287194928135
External references
- oeis: A151259