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 A195244 #8 Jul 22 2025 12:42:03 %S A195244 5,65,2729,357847,147824001,192172956591,786909681200387, %T A195244 10151817642632605643,412697709382902984293947, %U A195244 52873327059079066189496492173,21349480944940442832764307444766199 %N A195244 Number of lower triangles of an n X n 0..4 array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by two or less. %C A195244 Column 4 of A195248 %H A195244 R. H. Hardin, <a href="/A195244/b195244.txt">Table of n, a(n) for n = 1..12</a> %e A195244 Some solutions for n=5 %e A195244 ..0..........4..........3..........0..........3..........4..........4 %e A195244 ..2.0........3.3........1.3........2.2........2.3........4.2........4.4 %e A195244 ..2.0.1......2.2.2......1.2.2......4.3.1......4.2.3......4.2.0......2.4.4 %e A195244 ..0.2.0.2....0.2.0.1....1.1.2.4....4.3.2.3....2.3.3.3....4.2.0.0....3.3.3.3 %e A195244 ..0.1.2.2.1..0.2.2.1.1..1.3.3.4.3..3.3.2.3.2..4.3.1.2.4..3.2.1.2.0..1.3.1.2.1 %K A195244 nonn %O A195244 1,1 %A A195244 _R. H. Hardin_ Sep 13 2011