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 abscissa of the first peak equal to k.
A108438
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 abscissa of the first peak equal to k.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =3a(4) =2a(5) =1a(6) =24a(7) =18a(8) =13a(9) =7a(10) =3a(11) =1a(12) =172a(13) =130a(14) =96a(15) =55a(16) =28a(17) =12a(18) =4a(19) =1a(20) =1360a(21) =1034a(22) =772a(23) =458a(24) =249a(25) =119a(26) =50a(27) =18a(28) =5a(29) =1
External references
- oeis: A108438