A250951 - OEIS

A250951

Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.

%I #10 Nov 24 2018 08:11:25

%S 209,2744,36016,472712,6204344,81431944,1068793208,14027896712,

%T 184115958136,2416519505288,31716786410360,416282400363400,

%U 5463700975560056,71711002733396360,941205958384596856

%N Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.

%H R. H. Hardin, <a href="/A250951/b250951.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) - 24*a(n-2) - 8*a(n-3).

%F Empirical g.f.: x*(209 - 391*x - 128*x^2) / (1 - 15*x + 24*x^2 + 8*x^3). - _Colin Barker_, Nov 24 2018

%e Some solutions for n=3:

%e 1 0 0 1 1 1 0 1 0 1 0 0 1 0 1 1 0 0 1 0

%e 0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 1 1 0 1 1

%e 1 0 0 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 0 1

%e 0 0 0 1 0 0 1 1 0 1 0 1 1 0 0 0 0 0 1 1

%Y Column 3 of A250956.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 28 2014