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 A194501 #7 Jul 22 2025 12:33:59 %S A194501 4,64,4160,1048560,1073741824,4398046511104,72057594037927936 %N A194501 Number of lower triangles of an n X n 0..4 array with each element unequal to the sum mod 5 of its horizontal and vertical neighbors. %C A194501 Column 4 of A194505 %e A194501 Some solutions for 3X3 %e A194501 ..0......1......3......1......0......1......2......2......4......1......0 %e A194501 ..2.0....0.3....2.4....0.2....1.0....4.0....4.2....0.4....2.3....2.2....3.4 %e A194501 ..4.1.4..2.4.0..1.1.4..1.4.2..0.3.1..0.0.2..3.1.2..2.0.1..3.4.0..3.3.4..3.2.4 %K A194501 nonn %O A194501 1,1 %A A194501 _R. H. Hardin_ Aug 27 2011