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 height of last peak equal to k.
A109158
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 height of last peak equal to k.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =4a(4) =3a(5) =1a(6) =10a(7) =20a(8) =18a(9) =12a(10) =5a(11) =1a(12) =66a(13) =132a(14) =122a(15) =92a(16) =54a(17) =24a(18) =7a(19) =1a(20) =498a(21) =996a(22) =930a(23) =732a(24) =478a(25) =264a(26) =118a(27) =40a(28) =9a(29) =1
External references
- oeis: A109158