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 A267752 #6 Aug 12 2016 06:54:16 %S A267752 1,8,118,2386,54956,1350674,34568612,910791802,24537293344, %T A267752 672857207788,18718820026952,527018609703106,14988164468962816, %U A267752 429939684328203092,12424959589420164728,361409602487910188762,10572662501852062471576 %N A267752 Number of 4Xn arrays containing n copies of 0..4-1 with every element equal to or 1 greater than any north neighbor modulo 4 and the upper left element equal to 0. %C A267752 Row 4 of A267751. %H A267752 R. H. Hardin, <a href="/A267752/b267752.txt">Table of n, a(n) for n = 1..40</a> %e A267752 Some solutions for n=4 %e A267752 ..0..0..3..2....0..3..3..1....0..3..1..3....0..2..0..2....0..1..1..3 %e A267752 ..1..1..3..2....1..0..0..2....1..3..2..0....1..2..0..3....0..2..1..3 %e A267752 ..2..1..0..2....2..0..1..3....2..0..2..0....1..3..1..3....0..2..2..3 %e A267752 ..3..1..0..3....2..1..2..3....3..1..2..1....1..0..2..3....1..2..3..0 %Y A267752 Cf. A267751. %K A267752 nonn %O A267752 1,2 %A A267752 _R. H. Hardin_, Jan 20 2016