A127735 Triangle read by rows: A127701 * A002260 as infinite lower triangular matrices.

1, 3, 4, 4, 8, 9, 5, 10, 15, 16, 6, 12, 18, 24, 25, 7, 14, 21, 28, 35, 36, 8, 16, 24, 32, 40, 48, 49, 9, 18, 27, 36, 45, 54, 63, 64, 10, 20, 30, 40, 50, 60, 70, 80, 81, 11, 22, 33, 44, 55, 66, 77, 88, 99, 100, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 121, 13, 26, 39, 52, 65, 78, 91, 104, 117, 130, 143, 144

Offset: 1

Author

Gary W. Adamson, Jan 26 2007

Keywords

• nonn
• tabl

Examples

			First few rows of the triangle are:
1;
3, 4;
4, 8, 9;
5, 10, 15, 16;
6, 12, 18, 24, 25;
...
		

Crossrefs

Cf. A002260, A127701, A127736.

Formula

Row sums = A127736: (1, 7, 21, 46, 85, 141, ...).

T(n,n) = n^2. T(n,k) = k*(n+1), 1<=kR. J. Mathar, Jul 21 2009

Extensions

A-number of left factor in the definition corrected by R. J. Mathar, Jul 21 2009

a(19) corrected and more terms from Georg Fischer, Jun 05 2023