Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #8 Apr 17 2018 08:19:41
%S 338,2038,12278,72802,434174,2588842,15426974,91951882,548068238,
%T 3266618650,19470028382,116047125514,691674559982,4122582893626,
%U 24571800071294,146455111766122,872915295745934,5202830428855834
%N Number of (n+2) X 3 binary arrays with each 3 X 3 subblock singular.
%C Column 1 of A186052.
%H R. H. Hardin, <a href="/A186044/b186044.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = 5*a(n-1) + 4*a(n-2) + 18*a(n-3) - 40*a(n-4) - 24*a(n-5) - 72*a(n-6).
%F Empirical g.f.: 2*x*(169 + 174*x + 368*x^2 - 1412*x^3 - 1056*x^4 - 2304*x^5) / (1 - 5*x - 4*x^2 - 18*x^3 + 40*x^4 + 24*x^5 + 72*x^6). - _Colin Barker_, Apr 17 2018
%e Some solutions for 4 X 3:
%e ..1..1..0....0..0..0....1..1..0....0..1..0....0..0..0....0..0..1....1..1..1
%e ..0..0..0....0..1..0....1..1..0....1..1..0....0..1..1....0..1..1....0..0..0
%e ..0..1..0....0..0..0....1..0..0....0..0..0....0..0..0....0..1..1....1..1..0
%e ..1..1..1....0..0..1....0..1..0....1..0..0....0..0..0....0..0..1....1..1..1
%Y Cf. A186052.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 11 2011