A207939 - OEIS

%I #8 Mar 06 2018 08:54:39

%S 6,36,98,271,844,2706,8977,30168,102384,349069,1193648,4087980,

%T 14013419,48061824,164886926,565777111,1941543632,6663053798,

%U 22867234785,78480570100,269349014868,924424358989,3172699693492,10888986998392

%N Number of 3 X n 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 1 0 vertically.

%C Row 3 of A207938.

%H R. H. Hardin, <a href="/A207939/b207939.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) - a(n-2) - 20*a(n-3) + 10*a(n-4) + 28*a(n-5) - 9*a(n-6) - 15*a(n-7) + a(n-8) + 2*a(n-9) for n>10.

%F Empirical g.f.: x*(6 + 6*x - 76*x^2 - 63*x^3 + 247*x^4 + 189*x^5 - 223*x^6 - 171*x^7 + 29*x^8 + 26*x^9) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x - 5*x^2 + x^4)). - _Colin Barker_, Mar 06 2018

%e Some solutions for n=4:

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

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

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

%Y Cf. A207938.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 21 2012