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 A198980 #7 Jul 22 2025 13:07:50 %S A198980 52,174454,1112962873,7267830860056,47495195899845037, %T A198980 310387893630465965693,2028430770889558380053172, %U A198980 13256095277348005849607178346,86630544487196927129344081838138 %N A198980 Number of nX6 0..5 arrays with values 0..5 introduced in row major order and no element equal to any horizontal or vertical neighbor. %C A198980 Column 6 of A198982 %H A198980 R. H. Hardin, <a href="/A198980/b198980.txt">Table of n, a(n) for n = 1..28</a> %e A198980 Some solutions with all values from 0 to 5 for n=4 %e A198980 ..0..1..0..2..0..2....0..1..0..1..0..1....0..1..0..2..0..3....0..1..0..2..3..4 %e A198980 ..1..0..1..0..3..1....1..0..1..0..2..0....1..0..1..0..2..4....1..0..1..0..4..0 %e A198980 ..0..3..0..1..4..5....0..3..0..1..4..2....0..3..0..1..4..3....0..3..0..1..0..2 %e A198980 ..3..0..1..2..1..0....3..0..1..0..5..1....3..0..1..4..2..5....3..0..1..0..1..5 %K A198980 nonn %O A198980 1,1 %A A198980 _R. H. Hardin_ Nov 01 2011