A261698 Irregular triangle read by rows in which row n lists the odd divisors of n in the order as follows: the smallest, the largest, the second smallest, the second largest, the third smallest, the third largest, and so on.

1, 1, 1, 3, 1, 1, 5, 1, 3, 1, 7, 1, 1, 9, 3, 1, 5, 1, 11, 1, 3, 1, 13, 1, 7, 1, 15, 3, 5, 1, 1, 17, 1, 9, 3, 1, 19, 1, 5, 1, 21, 3, 7, 1, 11, 1, 23, 1, 3, 1, 25, 5, 1, 13, 1, 27, 3, 9, 1, 7, 1, 29, 1, 15, 3, 5, 1, 31, 1, 1, 33, 3, 11, 1, 17, 1, 35, 5, 7, 1, 9, 3, 1, 37, 1, 19, 1, 39, 3, 13, 1, 5, 1, 41, 1, 21, 3, 7, 1, 43, 1, 11, 1, 45, 3, 15, 5, 9

Offset: 1

Author

Omar E. Pol, Sep 21 2015

Keywords

• nonn
• tabf

Comments

Also the odd numbers of A210959.

Row lengths give A001227.

Row sums give A000593.

Another version of A182469 from which differs at a(14), or T(9,2).

For a similar version see A261697 from which differs at a(34), or T(18,2).

Examples

			List of divisors of 45 from distinct sequences:
45th row of triangle A182469: 1, 3, 5, 9, 15, 45.
45th row of triangle A261697: 1, 45, 3, 5, 15, 9.
45th row of this triangle...: 1, 45, 3, 15, 5, 9.
Triangle begins:
  1;
  1;
  1,  3;
  1;
  1,  5;
  1,  3;
  1,  7;
  1;
  1,  9,  3;
  1,  5;
  1, 11;
  1,  3;
  1, 13;
  1,  7;
  1, 15,  3,  5;
  1;
  1, 17;
  1,  9,  3;
  1, 19;
  1,  5;
  1, 21,  3,  7;
  ...
		

Crossrefs

Cf. A000593, A001227, A027750, A182469, A210959, A261697.