This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A273966 #3 Jun 05 2016 14:37:15 %S A273966 5,105,1946,24587,211121,2116450,15084593,112714143,511843593, %T A273966 2841058530,10796121020,48330908582 %N A273966 Number of nX3 0..3 arrays with no three equal values forming an isosceles triangle, and new values introduced in 0..3 order. %C A273966 Column 3 of A273968. %e A273966 Some solutions for n=4 %e A273966 ..0..1..2. .0..1..1. .0..1..2. .0..1..2. .0..1..2. .0..0..0. .0..0..1 %e A273966 ..0..2..3. .0..2..3. .1..0..2. .1..3..3. .3..1..2. .1..2..2. .2..3..3 %e A273966 ..3..3..1. .3..1..0. .1..0..2. .3..2..0. .2..2..0. .1..3..3. .3..2..0 %e A273966 ..0..1..2. .3..1..0. .1..0..2. .0..1..0. .0..3..0. .3..1..0. .3..1..1 %Y A273966 Cf. A273968. %K A273966 nonn %O A273966 1,1 %A A273966 _R. H. Hardin_, Jun 05 2016