A143355 Triangle read by rows: A051731 * A010766 as infinite lower triangular matrices.

1, 3, 1, 4, 1, 1, 7, 3, 1, 1, 6, 2, 1, 1, 1, 12, 5, 3, 1, 1, 1, 8, 3, 2, 1, 1, 1, 1, 15, 7, 3, 3, 1, 1, 1, 1, 13, 5, 4, 2, 1, 1, 1, 1, 1, 18, 8, 4, 3, 3, 1, 1, 1, 1, 1, 12, 5, 3, 2, 2, 1, 1, 1, 1, 1, 1, 28, 13, 8, 5, 3, 3, 1, 1, 1, 1, 1, 1

Offset: 1

Author

Gary W. Adamson, Aug 10 2008

Keywords

• nonn
• tabl

Comments

Left column = sigma(n), A000203.

Row sums = A143356: (1, 4, 56, 12, 11, 23, 17,...).

Examples

			First few rows of the triangle =
1;
3, 1;
4, 1, 1;
7, 3, 1, 1;
6, 2, 1, 1, 1;
12, 5, 3, 1, 1, 1;
8, 3, 2, 1, 1, 1, 1;
15, 7, 3, 3, 1, 1, 1, 1;
...
		

Crossrefs

Cf. A000203, A010766, A051731, A143356.

Extensions

a(72) split by Georg Fischer, May 29 2023