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 A195230 #8 Jul 22 2025 12:41:33 %S A195230 7,43,519,12259,570911,52683885,9661943973,3529267255201, %T A195230 2571928557261907,3744070741500225585,10898903552323266521821, %U A195230 63494356952926436300329797,740796894931520786982829942993 %N A195230 Number of lower triangles of an n X n 0..6 array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by one or less. %C A195230 Column 6 of A195232 %H A195230 R. H. Hardin, <a href="/A195230/b195230.txt">Table of n, a(n) for n = 1..15</a> %e A195230 Some solutions for n=4 %e A195230 ..6........4........5........4........2........2........3........2 %e A195230 ..5.5......4.4......4.5......4.4......2.3......2.2......4.4......1.2 %e A195230 ..5.6.5....4.4.3....4.4.4....5.5.5....3.3.3....2.2.2....3.3.3....1.1.1 %e A195230 ..6.6.5.4..4.3.3.4..3.4.4.3..5.6.5.6..2.2.2.3..1.2.1.1..3.4.4.3..1.0.1.1 %K A195230 nonn %O A195230 1,1 %A A195230 _R. H. Hardin_ Sep 13 2011