A253465 - OEIS

%I #9 Dec 14 2018 06:31:38

%S 24208,3072,2600,3744,7496,8272,15680,31824,94016,104272,224960,

%T 481104,1478336,1640272,3573440,7669584,23627456,26216272,57149120,

%U 122685264,378013376,419432272,914360000,1962936144,6048188096,6710888272

%N Number of (n+1) X (4+1) 0..2 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally, vertically, diagonally and antidiagonally.

%H R. H. Hardin, <a href="/A253465/b253465.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-2) + 16*a(n-4) - 16*a(n-6) for n>8.

%F Empirical g.f.: 8*x*(3026 + 384*x - 2701*x^2 + 84*x^3 - 47804*x^4 - 5578*x^5 + 44239*x^6 + 1600*x^7) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 + 4*x^2)). - _Colin Barker_, Dec 14 2018

%e Some solutions for n=4:

%e ..1..1..1..1..1....0..2..0..0..1....1..0..1..2..2....1..0..1..0..2

%e ..0..1..1..2..0....0..0..1..0..2....0..1..1..2..0....1..2..1..2..2

%e ..1..0..2..1..1....0..1..0..1..0....1..0..2..1..1....2..1..2..1..2

%e ..0..1..1..2..0....2..1..2..1..2....0..1..1..2..0....0..1..0..1..1

%e ..1..0..2..1..2....1..2..1..2..1....2..0..2..0..0....1..0..1..0..0

%Y Column 4 of A253468.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 01 2015