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 A222337 #8 Mar 15 2018 06:42:33 %S A222337 216,178746,147918906,122408393436,101297497221786,83827445649884946, %T A222337 69370328359709445996,57406526220963704077986, %U A222337 47506035082750189614687546,39313010520733216994188515036,32532978041867113135439462852106 %N A222337 Number of n X 4 0..6 arrays with no entry increasing mod 7 by 6 rightwards or downwards, starting with upper left zero. %C A222337 Column 4 of A222340. %H A222337 R. H. Hardin, <a href="/A222337/b222337.txt">Table of n, a(n) for n = 1..109</a> %F A222337 Empirical: a(n) = 873*a(n-1) - 38091*a(n-2) + 387974*a(n-3). %F A222337 Empirical g.f.: 6*x*(36 - 1637*x + 16884*x^2) / (1 - 873*x + 38091*x^2 - 387974*x^3). - _Colin Barker_, Mar 15 2018 %e A222337 Some solutions for n=3: %e A222337 ..0..0..2..0....0..2..2..0....0..2..0..0....0..2..0..0....0..2..2..0 %e A222337 ..0..3..5..0....0..3..3..0....0..5..3..0....0..0..2..0....0..3..4..0 %e A222337 ..0..3..1..1....2..3..3..5....3..3..4..4....3..5..6..3....0..3..0..1 %Y A222337 Cf. A222340. %K A222337 nonn %O A222337 1,1 %A A222337 _R. H. Hardin_, Feb 15 2013