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 A241252 #7 Apr 14 2015 08:33:35 %S A241252 10,12,71,446,3404,25190,225191,2057343,20539926,204332167,2101549932, %T A241252 21494785659,224464995283,2317825938537,24259559536660, %U A241252 251621814311194,2633451197372065,27369019127795259 %N A241252 Number of n X 5 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4. %C A241252 Column 5 of A241255. %e A241252 Some solutions for n=4: %e A241252 ..3..3..2..2..2....2..2..2..2..3....3..3..2..2..2....2..2..2..2..3 %e A241252 ..2..1..3..1..1....0..0..0..0..2....2..1..3..0..1....0..0..0..0..2 %e A241252 ..0..2..2..2..2....3..3..0..0..2....2..2..0..0..2....0..0..0..0..2 %e A241252 ..0..0..0..0..2....0..2..1..1..2....2..1..2..3..2....0..0..3..1..2 %Y A241252 Cf. A241255. %K A241252 nonn %O A241252 1,1 %A A241252 _R. H. Hardin_, Apr 18 2014