A131399 3*A007318 - A046854 - A065941.

1, 1, 1, 1, 4, 1, 1, 6, 6, 1, 1, 9, 12, 9, 1, 1, 11, 23, 23, 11, 1, 1, 14, 34, 52, 34, 14, 1, 1, 16, 51, 90, 90, 51, 16, 1, 1, 19, 67, 152, 180, 152, 67, 19, 1, 1, 21, 90, 225, 342, 342, 225, 90, 21, 1

Offset: 0

Author

Gary W. Adamson, Jul 05 2007

Keywords

• nonn
• tabl

Comments

Row sums = A074878: (1, 2, 6, 14, 32, 70, 150,...).

Examples

			First few rows of the triangle are:
1;
1, 1;
1, 4, 1;
1, 6, 6, 1;
1, 9, 12, 9, 1;
1, 11, 23, 23, 11, 1;
1, 14, 34, 52, 34, 14, 1;
1, 16, 51, 90, 90, 51, 16, 1;
...
		

Crossrefs

Cf. A007318, A046854, A065941, A074878.

Formula

3*A007318 - A046854 - A065941 as infinite lower triangular matrices.