Number of 2n-step paths from (0,0) to (0,n) that stay in the first quadrant (but may touch the axes) consisting of steps (-1,0), (0,1), (0,-1) and (1,-1).
A306813
Number of 2n-step paths from (0,0) to (0,n) that stay in the first quadrant (but may touch the axes) consisting of steps (-1,0), (0,1), (0,-1) and (1,-1).
Terms
- a(0) =1a(1) =0a(2) =3a(3) =10a(4) =20a(5) =237a(6) =770a(7) =3944a(8) =28635a(9) =112360a(10) =744084a(11) =4381083a(12) =21579779a(13) =143815322a(14) =801165187a(15) =4578481584a(16) =29176623983a(17) =165772480380
External references
- oeis: A306813