cp's OEIS Frontend

A202975 Number of nX4 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.

%I A202975 #7 Jul 22 2025 16:54:48
%S A202975 1,7,58,385,2582,17740,122468,846908,5858575,40519184,280214415,
%T A202975 1937863565,13401760093,92683431379,640976755990,4432841883249,
%U A202975 30656469034888,212012773252576,1466229429328620,10140090725898534
%N A202975 Number of nX4 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors.
%C A202975 Column 4 of A202979
%H A202975 R. H. Hardin, <a href="/A202975/b202975.txt">Table of n, a(n) for n = 1..210</a>
%F A202975 Empirical: a(n) = 10*a(n-1) -31*a(n-2) +82*a(n-3) -131*a(n-4) +226*a(n-5) -319*a(n-6) +206*a(n-7) -574*a(n-8) +483*a(n-9) -432*a(n-10) +517*a(n-11) +132*a(n-12) +746*a(n-13) -145*a(n-14) -228*a(n-15) -6*a(n-16) +41*a(n-17) +3*a(n-18) -3*a(n-19)
%e A202975 Some solutions for n=5
%e A202975 ..1..1..0..0....1..1..1..0....1..1..0..0....1..1..1..1....0..1..1..0
%e A202975 ..1..1..1..1....1..0..1..1....1..1..1..1....1..0..1..1....1..1..1..1
%e A202975 ..0..0..1..1....1..0..0..1....1..1..1..1....1..0..1..0....1..0..1..1
%e A202975 ..0..1..1..1....1..0..1..1....1..1..1..1....1..1..1..1....1..1..0..1
%e A202975 ..0..1..1..0....1..1..1..0....0..1..1..0....0..1..1..1....0..1..1..1
%K A202975 nonn
%O A202975 1,2
%A A202975 _R. H. Hardin_ Dec 26 2011