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

1,2

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.

Links

Table of n, a(n) for n=1..91.

Formula

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

Example

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.

Sequence in context: A206400 A321129 A278265 * A111629 A083953 A066400

Adjacent sequences: A171366 A171367 A171368 * A171370 A171371 A171372

Keyword

nonn,easy,tabl

Author

Gary W. Adamson, Dec 06 2009

Extensions

Description corrected by Robert Israel, Jan 03 2019

Status

approved