A143594 Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's).

1, 2, 2, 2, 2, 2, 3, 4, 2, 2, 2, 2, 2, 2, 2, 4, 6, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 6, 4, 4, 2, 2, 2, 2, 3, 4, 4, 2, 2, 2, 2, 2, 2, 4, 6, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 10, 8, 6, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset: 1

Author

Gary W. Adamson, Aug 26 2008

Keywords

• nonn
• tabl

Comments

Left column = d(n), A000005: (1, 2, 2, 3, 2, 4, 2,...).

Prime rows have all 2's.

Row sums = A129235: (1, 4, 6, 11, 10, 10,...).

Examples

			First few rows of the triangle =
1;
2, 2;
2, 2, 2;
3, 4, 2, 2;
2, 2, 2, 2, 2;
4, 6, 4, 2, 2, 2;
2, 2, 2, 2, 2, 2, 2;
...
		

Crossrefs

Cf. A129235, A000005, A051731.

Formula

Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's), i.e. (1; 1,2; 1,2,2;...), 1<=k<=n A051731 = the inverse Mobius transform.