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 A273963 #3 Jun 05 2016 14:17:37 %S A273963 15,1264,49702,543906,4010258,16365681,55643290,210405148,904155053, %T A273963 4384022592,21350702064,105038486755,514302715276,2558243582787 %N A273963 Number of nX4 0..3 arrays with no three equal values forming an isosceles right triangle, and new values introduced in 0..3 order. %C A273963 Column 4 of A273964. %e A273963 Some solutions for n=3 %e A273963 ..0..1..2..3. .0..1..0..1. .0..1..2..3. .0..1..1..0. .0..1..1..2 %e A273963 ..3..0..3..2. .2..1..2..2. .3..0..2..1. .0..2..2..0. .2..2..0..3 %e A273963 ..3..0..1..2. .2..3..1..0. .3..1..2..0. .0..3..1..0. .1..3..3..1 %Y A273963 Cf. A273964. %K A273963 nonn %O A273963 1,1 %A A273963 _R. H. Hardin_, Jun 05 2016