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=(1,2) steps among the steps leading to the first d step.
A108441
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=(1,2) steps among the steps leading to the first d step.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =6a(5) =1a(6) =15a(7) =39a(8) =11a(9) =1a(10) =97a(11) =284a(12) =100a(13) =16a(14) =1a(15) =721a(16) =2249a(17) =888a(18) =186a(19) =21a(20) =1a(21) =5827a(22) =18890a(23) =7977a(24) =1952a(25) =297a(26) =26a(27) =1a(28) =49759a(29) =165519
External references
- oeis: A108441