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), (0, 1), (1, -1)}.
A151256
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), (0, 1), (1, -1)}.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =23a(6) =61a(7) =153a(8) =418a(9) =1100a(10) =3064a(11) =8307a(12) =23447a(13) =64864a(14) =184825a(15) =518709a(16) =1488535a(17) =4222233a(18) =12183197a(19) =34838780a(20) =100966510a(21) =290552075a(22) =845040527a(23) =2444044917a(24) =7129099964a(25) =20703110094a(26) =60537979132a(27) =176393527768a(28) =516869732557
External references
- oeis: A151256