A109221 A number triangle related to the Fibonacci polynomials.

1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 5, 3, 1, 1, 1, 7, 5, 6, 1, 1, 1, 9, 7, 15, 6, 1, 1, 1, 11, 9, 28, 15, 10, 1, 1, 1, 13, 11, 45, 28, 35, 10, 1, 1, 1, 15, 13, 66, 45, 84, 35, 15, 1, 1, 1, 17, 15, 91, 66, 165, 84, 70, 15, 1, 1, 1, 19, 17, 120, 91, 286, 165, 210, 70, 21, 1, 1, 1, 21, 19

Offset: 0

Author

Paul Barry, Jun 22 2005

Keywords

• easy
• nonn
• tabl

Comments

The repeated columns are made up by taking every second element of columns in A011973. Row sums are A109222.

Examples

			Rows begin
1;
1,1;
1,1,1;
1,1,3,1;
1,1,5,3,1;
1,1,7,5,6,1;
		

Formula

Number triangle T(n, k)=binomial(floor((2n-k)/2)+n-k, 2n-2k)