A278597 One half of A278481.

1, 2, 2, 2, 3, 2, 2, 3, 3, 2, 2, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2

Offset: 1

Author

Omar E. Pol, Nov 23 2016

Keywords

• nonn
• tabl

Comments

Apart from the left border and the right border, the rest of the elements are 3's.

Examples

			The sequence written as a triangle begins:
                      1;
                    2,  2;
                  2,  3,  2;
                2,  3,  3,  2;
              2,  3,  3,  3,  2;
            2,  3,  3,  3,  3,  2;
          2,  3,  3,  3,  3,  3,  2;
        2,  3,  3,  3,  3,  3,  3,  2;
      2,  3,  3,  3,  3,  3,  3,  3,  2;
    2,  3,  3,  3,  3,  3,  3,  3,  3,  2;
  ...
		

Crossrefs

Row sums give A016777.

Left border gives A040000, the same as the right border.

Middle column gives A122553.

Every diagonal that is parallel to any of the borders gives the elements greater than 1 of A158799.

Cf. A278481.

Formula

a(n) = A278481(n)/2.