# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a230983 Showing 1-1 of 1 %I A230983 #8 Sep 25 2018 08:53:14 %S A230983 1,1,4,5,15,20,57,77,218,295,835,1130,3199,4329,12256,16585,46955, %T A230983 63540,179893,243433,689202,932635,2640455,3573090,10116051,13689141, %U A230983 38756384,52445525,148482575,200928100,568863057,769791157,2179415178,2949206335 %N A230983 Number of white square subarrays of (n+1) X (2+1) binary arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with upper left element zero. %H A230983 R. H. Hardin, Table of n, a(n) for n = 1..210 %F A230983 Empirical: a(n) = 5*a(n-2) - 5*a(n-4) + 2*a(n-6). %F A230983 Empirical g.f.: x*(1 + x - x^2) / (1 - 5*x^2 + 5*x^4 - 2*x^6). - _Colin Barker_, Sep 25 2018 %e A230983 Some solutions for n=6: %e A230983 ..0..x..0....0..x..0....0..x..0....0..x..0....0..x..0....0..x..0....0..x..0 %e A230983 ..x..1..x....x..1..x....x..1..x....x..1..x....x..1..x....x..1..x....x..1..x %e A230983 ..0..x..0....0..x..0....0..x..0....1..x..0....0..x..1....1..x..1....0..x..1 %e A230983 ..x..0..x....x..0..x....x..1..x....x..0..x....x..0..x....x..0..x....x..0..x %e A230983 ..1..x..1....1..x..1....1..x..1....1..x..0....1..x..0....1..x..0....1..x..1 %e A230983 ..x..1..x....x..0..x....x..0..x....x..1..x....x..1..x....x..1..x....x..0..x %e A230983 ..0..x..0....1..x..1....1..x..1....0..x..0....0..x..0....0..x..0....1..x..1 %Y A230983 Column 2 of A230989. %K A230983 nonn %O A230983 1,3 %A A230983 _R. H. Hardin_, Nov 02 2013 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE