A128306 Triangle read by rows: A054521 * A007318 as infinite lower triangular matrices.

1, 1, 0, 2, 1, 0, 2, 2, 1, 0, 4, 6, 4, 1, 0, 2, 4, 6, 4, 1, 0, 6, 15, 20, 15, 6, 1, 0, 4, 12, 22, 24, 16, 6, 1, 0, 6, 21, 45, 60, 51, 27, 8, 1, 0, 4, 16, 44, 76, 85, 62, 29, 8, 1, 0, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1, 0, 4, 20, 66, 144, 226, 258, 211, 120, 45, 10, 1, 0

Offset: 1

Author

Gary W. Adamson, Feb 25 2007

Keywords

• nonn
• tabl

Comments

Left border = phi(n), A000010: (1, 1, 2, 2, 4, 2, 6, ...). Row sums = A054432: (1, 1, 3, 5, 15, 17, 63, ...).

Examples

			First few rows of the triangle:
  1;
  1,  0;
  2,  1,  0;
  2,  2,  1,  0;
  4,  6,  4,  1,  0;
  2,  4,  6,  4,  1,  0;
  6, 15, 20, 15,  6,  1,  0;
  ...
		

Crossrefs

Cf. A000010, A007318, A054432, A054521.

Extensions

Definition amended and terms starting at a(56) corrected by Georg Fischer, May 29 2023