A131844 3*A131821 - 2.

1, 4, 4, 7, 1, 7, 10, 1, 1, 10, 13, 1, 1, 1, 13, 16, 1, 1, 1, 1, 16, 19, 1, 1, 1, 1, 1, 19, 22, 1, 1, 1, 1, 1, 1, 22, 25, 1, 1, 1, 1, 1, 1, 1, 25, 28, 1, 1, 1, 1, 1, 1, 1, 1, 28, 31, 1, 1, 1, 1, 1, 1, 1, 1, 1, 31, 34, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 34, 37, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 37, 40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 40

Offset: 0

Author

Gary W. Adamson, Jul 22 2007

Keywords

• nonn
• tabl

Comments

Row sums = A016993, (7n + 1): (1, 8, 15, 22, 29, ...).

Examples

			First few rows of the triangle:
   1;
   4,  4;
   7,  1,  7;
  10,  1,  1, 10;
  13,  1,  1,  1, 13;
  16,  1,  1,  1,  1, 16;
  ...
		

Crossrefs

Cf. A131821, A016993.

Formula

3*A131821 - 2 as infinite lower triangular matrices.

Infinite lower triangular matrix, (3n + 1): (1, 4, 7, 10, ...) as right and left borders and the rest 1's.

Extensions

More terms from Russ Cox, Apr 18 2024