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 A240004 #7 Jun 02 2025 09:37:39 %S A240004 66,1117,10405,86360,635873,4267171,26152051,147439332,775122753, %T A240004 3821059149,17769229031,78356711183,328981383567,1319877073978, %U A240004 5076715532082,18776009861766,66950026301586,230700526217982 %N A240004 Number of 5Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. %C A240004 Row 5 of A240000 %H A240004 R. H. Hardin, <a href="/A240004/b240004.txt">Table of n, a(n) for n = 1..210</a> %H A240004 R. H. Hardin, <a href="/A240004/a240004.txt">Empirical polynomial of degree 44</a> %F A240004 Empirical polynomial of degree 44 (see link above) %e A240004 Some solutions for n=3 %e A240004 ..0..3..3....0..3..3....0..0..3....0..0..3....0..0..3....3..3..0....3..3..0 %e A240004 ..0..3..3....0..0..3....0..0..0....0..0..0....0..3..2....2..2..3....0..3..1 %e A240004 ..3..3..1....0..0..3....3..3..0....0..3..2....0..3..1....2..2..0....2..2..0 %e A240004 ..0..2..2....0..2..0....0..3..3....0..2..1....3..3..2....0..0..2....0..0..0 %e A240004 ..0..2..1....0..0..0....0..2..2....0..2..2....2..1..3....0..0..2....2..0..1 %K A240004 nonn %O A240004 1,1 %A A240004 _R. H. Hardin_, Mar 30 2014