A114114 An invertible partition matrix.

1, 1, 1, 0, 2, 1, 0, 1, 2, 1, 0, 0, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 0, 2, 2, 2, 1, 0, 0, 0, 1, 2, 2, 2, 1, 0, 0, 0, 0, 2, 2, 2, 2, 1, 0, 0, 0, 0, 1, 2, 2, 2, 2, 1, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 1, 0, 0, 0, 0, 0, 1, 2, 2, 2, 2, 2, 1, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 1

Offset: 0

Author

Paul Barry, Nov 13 2005

Keywords

• easy
• nonn
• tabl

Comments

Row sums are n+1, A000027. Diagonal sums are 1,1,1,2,2,2,3,3,3,.... or A008620. Inverse is A114115. Product with first difference matrix (1-x,x) is A114117.

Examples

			Triangle begins
1.................=1
1,1...............=2
0,2,1.............=3
0,1,2,1...........=4
0,0,2,2,1.........=5
0,0,1,2,2,1.......=6
0,0,0,2,2,2,1.....=7
0,0,0,1,2,2,2,1...=8
		

Formula

Number triangle T(n, k)=sum{j=0..n, C(floor((n+j)/2), k)C(k, floor((n+j)/2))}.