A171369 - OEIS

%I #11 Jan 04 2019 09:02:02

%S 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,

%T 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,

%U 3,3,3,3,3,3,3,3,3,3,3,3,1,3,3,3,3,3,3,3,3,3,3

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

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

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

%e First few rows of the triangle =

%e .

%e 1;

%e 3, 3;

%e 1, 3, 3;

%e 3, 3, 1, 3;

%e 3, 3, 3, 3, 3;

%e 1, 3, 3, 3, 3, 3;

%e 3, 3, 3, 1, 3, 3, 3;

%e 3, 3, 3, 3, 3, 3, 3, 1;

%e ...

%Y Cf. A169695, A275437.

%K nonn,easy,tabl

%O 1,2

%A _Gary W. Adamson_, Dec 06 2009

%E Description corrected by _Robert Israel_, Jan 03 2019