A233885 - OEIS

%I #9 Oct 12 2018 08:29:21

%S 112,384,1264,4292,14272,48300,161168,544460,1820160,6141480,20556600,

%T 69298740,232159624,782096432,2621850152,8827674288,29608245144,

%U 99647390252,334350373304,1124887110036,3775523491352,12698981481044

%N Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 30, and no two adjacent values equal.

%H R. H. Hardin, <a href="/A233885/b233885.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 18*a(n-2) + 4*a(n-3) - 95*a(n-4) - 30*a(n-5) + 165*a(n-6) + 36*a(n-7) - 105*a(n-8) - 8*a(n-9) + 20*a(n-10).

%F Empirical g.f.: 4*x*(28 + 96*x - 188*x^2 - 767*x^3 + 156*x^4 + 1457*x^5 + 56*x^6 - 940*x^7 - 22*x^8 + 180*x^9) / ((1 + x)*(1 - x - 17*x^2 + 13*x^3 + 82*x^4 - 52*x^5 - 113*x^6 + 77*x^7 + 28*x^8 - 20*x^9)). - _Colin Barker_, Oct 12 2018

%e Some solutions for n=5:

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

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

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

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

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

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

%Y Column 1 of A233892.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 17 2013