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 A224115 #8 Feb 06 2023 11:56:02 %S A224115 282,1434,4182,9762,19110,34602,56982,89766,134298,194262,271074, %T A224115 371478,494346,647358,833226,1057542,1321482,1636314,1999926,2425794, %U A224115 2913678,3472242,4104942,4828626 %N A224115 Number of idempotent 4X4 0..n matrices of rank 2. %e A224115 Some solutions for n=3 %e A224115 ..0..0..0..0....1..0..0..0....0..0..0..0....0..0..0..0....1..0..0..0 %e A224115 ..1..1..0..0....0..1..1..0....1..1..0..0....1..1..0..0....0..1..0..0 %e A224115 ..2..1..0..1....0..0..0..0....0..0..1..0....1..1..0..1....2..2..0..0 %e A224115 ..1..0..0..1....0..3..3..0....0..0..1..0....0..0..0..1....0..3..0..0 %Y A224115 Row 4 of A224114. %K A224115 nonn,more %O A224115 1,1 %A A224115 _R. H. Hardin_, Apr 09 2013