cp's OEIS Frontend

A209651 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 0 1 vertically.

%I A209651 #7 Jul 22 2025 21:52:54
%S A209651 8,64,216,630,2156,7128,24990,87136,311040,1112150,4018716,14563584,
%T A209651 53065350,193861408,710502760,2609417910,9603620076,35401092264,
%U A209651 130688898510,483039609408,1787282764624,6619084515926,24532925650268
%N A209651 Number of 4Xn 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 0 1 vertically.
%C A209651 Row 4 of A209650
%H A209651 R. H. Hardin, <a href="/A209651/b209651.txt">Table of n, a(n) for n = 1..210</a>
%F A209651 Empirical: a(n) = 9*a(n-1) -11*a(n-2) -108*a(n-3) +272*a(n-4) +480*a(n-5) -1754*a(n-6) -942*a(n-7) +5482*a(n-8) +552*a(n-9) -9304*a(n-10) +888*a(n-11) +8539*a(n-12) -1755*a(n-13) -3871*a(n-14) +1092*a(n-15) +648*a(n-16) -216*a(n-17) for n>18
%e A209651 Some solutions for n=4
%e A209651 ..1..1..1..1....1..0..1..0....1..0..1..0....1..1..0..1....1..0..1..1
%e A209651 ..1..1..1..1....1..0..1..0....0..0..0..0....0..0..0..0....1..1..0..1
%e A209651 ..1..1..1..1....1..0..1..0....0..0..0..0....0..0..0..0....0..1..0..1
%e A209651 ..1..1..1..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
%K A209651 nonn
%O A209651 1,1
%A A209651 _R. H. Hardin_ Mar 11 2012