A109960 Number triangle binomial(n+3k,4k).

1, 1, 1, 1, 5, 1, 1, 15, 9, 1, 1, 35, 45, 13, 1, 1, 70, 165, 91, 17, 1, 1, 126, 495, 455, 153, 21, 1, 1, 210, 1287, 1820, 969, 231, 25, 1, 1, 330, 3003, 6188, 4845, 1771, 325, 29, 1, 1, 495, 6435, 18564, 20349, 10626, 2925, 435, 33, 1, 1, 715, 12870, 50388, 74613, 53130

Offset: 0

Author

Paul Barry, Jul 06 2005

Keywords

• easy
• nonn
• tabl

Comments

Riordan array (1/(1-x), x/(1-x)^4). Rows sums are A055988. Diagonal sums are A109961. Inverse array is A109962.

Examples

			Rows begin
1;
1,1;
1,5,1;
1,15,9,1;
1,35,45,13,1;
1,70,165,91,17,1;
		

Formula

Number triangle T(n, k)=binomial(n+3k, 4k)