A073187 Triangle of C(n+1,k)*C(2*n-3*k,n-3*k)/(n+1) by rows.

1, 1, 2, 5, 1, 14, 5, 42, 21, 132, 84, 3, 429, 330, 28, 1430, 1287, 180, 4862, 5005, 990, 12, 16796, 19448, 5005, 165, 58786, 75582, 24024, 1430, 208012, 293930, 111384, 10010, 55, 742900, 1144066, 503880, 61880, 1001, 2674440, 4457400, 2238390

Offset

1,3

Links

G. C. Greubel, Rows n=0..150 of triangle, flattened

Example

1;
1;
2;
5,  1;
14, 5;
42, 21;
132, 84, 3;
429, 330, 28;
1430, 1287, 180; ...

Mathematica

T[n_, k_]:= If[k < 0 || k > n/3, 0, Binomial[n + 1, k]*Binomial[2*n - 3*k, n - 3*k]/(n + 1)]; Table[T[n, k], {n, 0, 10}, {k, 0, Floor[n/3]}]//Flatten (* G. C. Greubel, May 29 2018 *)

Prog

(PARI) alias(C, binomial); T(n, k)=if(k<0 || k>n/3, 0, C(n+1, k)*C(2*n-3*k, n-3*k)/(n+1))

Crossrefs

Row sums give A071969.

Sequence in context: A114494 A118964 A263771 * A377443 A138159 A118919

Adjacent sequences: A073184 A073185 A073186 * A073188 A073189 A073190

Keyword

nonn,tabf

Author

Michael Somos, Jul 19 2002

Status

approved