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 A241058 #6 Jun 02 2025 10:01:26 %S A241058 8,8,6,132,598,1392,10921,72769,370453,1671155,9384164,51783699, %T A241058 208252518,1150802650,6121081737,27887287923,140605229939, %U A241058 756558481056,3755762723973,18153596088044,90862001756655,469665600883273 %N A241058 Number of 5Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4. %C A241058 Row 5 of A241054 %H A241058 R. H. Hardin, <a href="/A241058/b241058.txt">Table of n, a(n) for n = 1..31</a> %e A241058 Some solutions for n=4 %e A241058 ..3..2..3..3....3..2..3..3....3..3..2..3....3..3..2..3....3..3..2..2 %e A241058 ..2..1..1..0....2..1..1..0....2..1..1..0....2..1..1..0....2..1..1..3 %e A241058 ..2..0..2..2....2..0..2..0....3..3..2..2....3..3..2..2....2..1..1..2 %e A241058 ..2..1..1..0....2..1..3..0....3..1..2..0....3..2..0..0....2..0..2..2 %e A241058 ..2..1..2..0....3..1..0..2....2..2..2..0....2..2..3..3....3..3..1..3 %K A241058 nonn %O A241058 1,1 %A A241058 _R. H. Hardin_, Apr 15 2014