A222337 - OEIS

%I #8 Mar 15 2018 06:42:33

%S 216,178746,147918906,122408393436,101297497221786,83827445649884946,

%T 69370328359709445996,57406526220963704077986,

%U 47506035082750189614687546,39313010520733216994188515036,32532978041867113135439462852106

%N 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 Column 4 of A222340.

%H R. H. Hardin, <a href="/A222337/b222337.txt">Table of n, a(n) for n = 1..109</a>

%F Empirical: a(n) = 873*a(n-1) - 38091*a(n-2) + 387974*a(n-3).

%F 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 Some solutions for n=3:

%e ..0..0..2..0....0..2..2..0....0..2..0..0....0..2..0..0....0..2..2..0

%e ..0..3..5..0....0..3..3..0....0..5..3..0....0..0..2..0....0..3..4..0

%e ..0..3..1..1....2..3..3..5....3..3..4..4....3..5..6..3....0..3..0..1

%Y Cf. A222340.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 15 2013