Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having k u=(2,1) steps among the steps leading to the first d step.
A108440
Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having k u=(2,1) steps among the steps leading to the first d step.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =5a(4) =4a(5) =1a(6) =33a(7) =25a(8) =7a(9) =1a(10) =249a(11) =184a(12) =54a(13) =10a(14) =1a(15) =2033a(16) =1481a(17) =446a(18) =92a(19) =13a(20) =1a(21) =17485a(22) =12620a(23) =3863a(24) =846a(25) =139a(26) =16a(27) =1a(28) =156033a(29) =111889
External references
- oeis: A108440