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 A194538 #7 Jul 22 2025 12:34:52 %S A194538 1,4,132,67377,543350470,40994098419294,21253155706215768591, %T A194538 71381360690596538575641162 %N A194538 Number of lower triangles of an n X n 0..6 array with new values introduced in row major order 0..6 and no element equal to more than one horizontal or vertical neighbor. %C A194538 Column 6 of A194540 %e A194538 Some solutions for 3X3 %e A194538 ..0......0......0......0......0......0......0......0......0......0......0 %e A194538 ..0.1....1.2....1.2....1.1....1.2....1.2....1.1....1.0....0.1....1.2....1.1 %e A194538 ..2.2.0..1.0.2..0.3.3..2.0.0..2.3.4..2.0.0..2.2.3..2.1.3..2.3.0..2.3.1..2.0.1 %K A194538 nonn %O A194538 1,2 %A A194538 _R. H. Hardin_ Aug 28 2011