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 A194500 #7 Jul 22 2025 12:33:51 %S A194500 3,27,776,59052,14348907,10460353203,22876792454961,150094717239776832 %N A194500 Number of lower triangles of an n X n 0..3 array with each element unequal to the sum mod 4 of its horizontal and vertical neighbors. %C A194500 Column 3 of A194505 %e A194500 Some solutions for 3X3 %e A194500 ..0......1......1......1......2......1......3......2......2......1......1 %e A194500 ..1.3....3.1....0.3....2.0....3.2....0.0....1.3....1.3....0.2....0.3....3.3 %e A194500 ..1.1.3..2.0.2..1.2.3..3.0.2..1.1.3..2.3.0..1.1.2..2.0.1..2.3.1..3.2.3..0.3.1 %K A194500 nonn %O A194500 1,1 %A A194500 _R. H. Hardin_ Aug 27 2011