A206320 - OEIS

%I #9 Jun 15 2018 09:56:09

%S 256,1344,10504,83088,673124,5432884,43848120,353716772,2853265228,

%T 23015359308,185649551836,1497511097624,12079428217088,97436737226308,

%U 785957567591456,6339798686936496,51138953368767152,412504036786299552

%N Number of (n+1) X 2 0..3 arrays with every 2 X 3 or 3 X 2 subblock having exactly three clockwise edge increases.

%C Column 1 of A206327.

%H R. H. Hardin, <a href="/A206320/b206320.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 9*a(n-1) - 5*a(n-2) - 26*a(n-3) + 42*a(n-4) + 19*a(n-5) + 42*a(n-6) + 14*a(n-7) for n>8.

%F Empirical g.f.: 4*x*(64 - 240*x - 78*x^2 + 482*x^3 + 511*x^4 + 500*x^5 + 154*x^6 + 8*x^7) / (1 - 9*x + 5*x^2 + 26*x^3 - 42*x^4 - 19*x^5 - 42*x^6 - 14*x^7). - _Colin Barker_, Jun 15 2018

%e Some solutions for n=4:

%e ..0..0....3..2....1..1....1..1....3..2....3..2....1..3....0..3....2..2....3..1

%e ..1..1....1..1....2..2....3..3....0..1....0..3....2..2....0..0....0..3....0..1

%e ..3..2....3..2....1..0....1..0....3..2....3..0....0..3....3..2....3..2....3..2

%e ..0..3....0..3....0..3....2..1....1..1....1..3....2..1....2..1....0..3....0..0

%e ..1..0....1..0....1..0....1..3....0..2....2..1....1..0....3..2....1..0....3..1

%Y Cf. A206327.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 06 2012