A131230 Triangle read by rows: 2*A130296 - A128174.

1, 4, 1, 5, 2, 1, 8, 1, 2, 1, 9, 2, 1, 2, 1, 12, 1, 2, 1, 2, 1, 13, 2, 1, 2, 1, 2, 1, 16, 1, 2, 1, 2, 1, 2, 1, 17, 2, 1, 2, 1, 2, 1, 2, 1, 20, 1, 2, 1, 2, 1, 2, 1, 2, 1, 21, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 24, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 25, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1

Offset: 1

Author

Gary W. Adamson, Jun 20 2007

Keywords

• nonn
• tabl

Comments

Left column = A042948, numbers congruent to {1,0} mod 4: (1, 4, 5, 8, 9, 12, ...).

Row sums = A047383, numbers congruent to {1,5} mod 7: (1, 5, 8, 12, 15, ...).

Examples

			First few rows of the triangle:
   1;
   4, 1;
   5, 2, 1;
   8, 1, 2, 1;
   9, 2, 1, 2, 1;
  12, 1, 2, 1, 2, 1;
  ...
		

Crossrefs

Cf. A047383, A042948, A128174, A131231, A130296.

Extensions

Incorrect formula removed and more terms from Georg Fischer, Jun 08 2023