A193635 Triangle: T(n,k)=C(3n-k,k), 0<=k<=n.

1, 1, 2, 1, 5, 6, 1, 8, 21, 20, 1, 11, 45, 84, 70, 1, 14, 78, 220, 330, 252, 1, 17, 120, 455, 1001, 1287, 924, 1, 20, 171, 816, 2380, 4368, 5005, 3432, 1, 23, 231, 1330, 4845, 11628, 18564, 19448, 12870, 1, 26, 300, 2024, 8855, 26334, 54264, 77520, 75582

Offset

0,3

Links

Table of n, a(n) for n=0..53.

Formula

T(n,k)=C(3n-k,k), 0<=k<=n.

Example

First 5 rows of A193635:
1
1...2
1...7....10
1...15...66....82
1...26...231...811...930

Mathematica

p[n_, k_] := Binomial[3 n - k, k];
Table[p[n, k], {n, 0, 9}, {k, 0, n}]  (* A193635 *)
Flatten[%]

Crossrefs

Cf. A193636.

Sequence in context: A193816 A335136 A193722 * A241168 A145324 A260613

Adjacent sequences: A193632 A193633 A193634 * A193636 A193637 A193638

Keyword

nonn,tabl

Author

Clark Kimberling, Aug 01 2011

Status

approved