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 A240415 #6 Jun 02 2025 09:56:17 %S A240415 25,139,1526,11670,74655,773196,5429095,41264901,368615027,2585037182, %T A240415 21489185687,174817614437,1291058701632,10769864002354,83962833112352, %U A240415 648485033420957,5301967970926934,40960040109260355,323977574986307633 %N A240415 Number of 4Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4. %C A240415 Row 4 of A240412 %H A240415 R. H. Hardin, <a href="/A240415/b240415.txt">Table of n, a(n) for n = 1..210</a> %e A240415 Some solutions for n=4 %e A240415 ..3..2..2..2....2..3..2..2....2..3..3..3....3..2..3..2....2..3..2..2 %e A240415 ..2..1..0..0....2..3..2..0....2..1..2..2....1..2..1..2....2..1..0..0 %e A240415 ..3..1..2..0....2..1..2..0....3..0..1..3....2..0..3..2....3..0..1..1 %e A240415 ..3..2..0..0....1..3..1..2....1..2..1..3....1..0..3..1....1..0..3..1 %K A240415 nonn %O A240415 1,1 %A A240415 _R. H. Hardin_, Apr 04 2014