A160798 a(n) = A160797(n+2)/3.

1, 7, 1, 7, 3, 21, 1, 7, 3, 21, 3, 21, 9, 63, 1, 7, 3, 21, 3, 21, 9, 63, 3, 21, 9, 63, 9, 63, 27, 189, 1, 7, 3, 21, 3, 21, 9, 63, 3, 21, 9, 63, 9, 63, 27, 189, 3, 21, 9, 63, 9, 63, 27, 189, 9, 63, 27, 189, 27, 189, 81, 567, 1, 7, 3, 21, 3, 21, 9, 63, 3, 21, 9, 63

Offset: 1

Author

Omar E. Pol, Jun 13 2009

Keywords

• nonn
• tabf

Comments

From Omar E. Pol, Mar 15 2020: (Start)

It appears that the right border of triangle gives A005032.

It appears that the sum of n-th row equals A004171(n). (End)

Apparently A160417 shifted once left. - R. J. Mathar, May 30 2025

Examples

			From _Omar E. Pol_, Mar 15 2020: (Start)
Written as an irregular triangle in which row lengths are the even powers of 2, the sequence begins:
1, 7;
1, 7, 3, 21;
1, 7, 3, 21, 3, 21, 9, 63;
1, 7, 3, 21, 3, 21, 9, 63, 3, 21, 9, 63, 9, 63, 27, 189;
1, 7, 3, 21, 3, 21, 9, 63, 3, 21, 9, 63, 9, 63, 27, 189, 3, 21, 9, 63, 9, 63, ...
(End)
		

Crossrefs

Cf. A004171, A005032, A160796, A160797.

Extensions

More terms from Jinyuan Wang, Mar 15 2020