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 A194539 #7 Jul 22 2025 12:34:59 %S A194539 1,4,132,68106,703256449,108504879480483,153378412416345530447 %N A194539 Number of lower triangles of an n X n 0..7 array with new values introduced in row major order 0..7 and no element equal to more than one horizontal or vertical neighbor. %C A194539 Column 7 of A194540 %e A194539 Some solutions for 3X3 %e A194539 ..0......0......0......0......0......0......0......0......0......0......0 %e A194539 ..1.1....1.1....1.0....1.2....0.1....1.2....1.2....1.2....0.1....1.2....1.2 %e A194539 ..2.2.0..0.2.0..0.2.3..1.3.3..2.3.1..0.3.4..1.3.2..2.0.3..2.2.1..0.3.2..0.1.2 %K A194539 nonn %O A194539 1,2 %A A194539 _R. H. Hardin_ Aug 28 2011