A143902 Rectangular array R by antidiagonals: R(m,n) = number of black squares.

0, 1, 1, 1, 2, 1, 2, 3, 3, 2, 2, 4, 4, 4, 2, 3, 5, 6, 6, 5, 3, 3, 6, 7, 8, 7, 6, 3, 4, 7, 9, 10, 10, 9, 7, 4, 4, 8, 10, 12, 12, 12, 10, 8, 4, 5, 9, 12, 14, 15, 15, 14, 12, 9, 5, 5, 10, 13, 16, 17, 18, 17, 16, 13, 10, 5, 6, 11, 15, 18, 20, 21, 21, 20, 18, 15, 11, 6, 6, 12, 16, 20, 22

Offset: 1

Author

Clark Kimberling, Sep 04 2008

Keywords

• nonn
• tabl

Comments

Antidiagonal sums: (2,4,10,16,28,40,60,80,...)=A006584 (conjectured).

Diagonals: A007590, A000217.

Examples

			Northwest corner:
0 1 1 2 2 3 3 4
1 2 3 4 5 6 7 8
1 3 4 6 7 9 10 12
2 4 6 8 10 12 14 16
		

Crossrefs

Cf. A143901.

Formula

R(m,n)=Floor(mn/2).