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 A240150 #6 Jun 02 2025 09:40:23 %S A240150 7,19,107,676,3993,22412,131005,731518,4144347,23263202,131973267, %T A240150 742448151,4200516883,23673251649,133792056873,754644250144, %U A240150 4262766555182,24053911144152,135834058269434,766651910127519 %N A240150 Number of nX4 0..3 arrays with no element equal to one plus the sum of elements to its left or one 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 A240150 Column 4 of A240153 %H A240150 R. H. Hardin, <a href="/A240150/b240150.txt">Table of n, a(n) for n = 1..210</a> %e A240150 Some solutions for n=4 %e A240150 ..3..2..3..3....3..2..3..2....3..3..2..3....2..2..3..2....2..2..3..2 %e A240150 ..3..2..1..1....3..2..1..1....2..1..2..1....0..2..1..2....0..2..1..1 %e A240150 ..2..2..3..2....2..2..0..2....0..0..3..3....2..2..0..3....0..2..2..3 %e A240150 ..3..2..1..2....2..0..0..1....0..3..2..3....2..0..2..2....0..2..2..2 %K A240150 nonn %O A240150 1,1 %A A240150 _R. H. Hardin_, Apr 02 2014