A171369 Triangle read by rows, replace 2's with 3's in A169695.

1, 3, 3, 1, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3

Offset: 1

Author

Gary W. Adamson, Dec 06 2009

Keywords

• nonn
• easy
• tabl

Comments

Given triangle A275437 (wrapped to contain n terms per row) or sequence A169695, replace 2's with 3's, other terms remain as is.

Examples

			First few rows of the triangle =
.
1;
3, 3;
1, 3, 3;
3, 3, 1, 3;
3, 3, 3, 3, 3;
1, 3, 3, 3, 3, 3;
3, 3, 3, 1, 3, 3, 3;
3, 3, 3, 3, 3, 3, 3, 1;
...
		

Crossrefs

Cf. A169695, A275437.

Formula

T(n,k) = 1 if n*(n-1)/2+k is a square, otherwise T(n,k) = 3.

Extensions

Description corrected by Robert Israel, Jan 03 2019