A235947 - OEIS

%I #8 Oct 20 2018 10:22:55

%S 81,294,905,2584,7353,20800,58896,167240,474948,1344000,3811120,

%T 10818624,30677136,86900480,246546816,699399552,1982514496,5620085760,

%U 15943384320,45209722880,128165455104,363441340416,1030800314368,2922637780992

%N Number of (n+1) X (1+1) 0..2 arrays colored with the upper median value of each 2 X 2 subblock.

%H R. H. Hardin, <a href="/A235947/b235947.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-3) + 36*a(n-4) + 48*a(n-6) for n>9.

%F Empirical g.f.: x*(81 + 294*x + 905*x^2 + 1936*x^3 + 2085*x^4 + 2976*x^5 + 1756*x^6 + 1280*x^7 + 400*x^8) / (1 - 8*x^3 - 36*x^4 - 48*x^6). - _Colin Barker_, Oct 20 2018

%e Some solutions for n=5:

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

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

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

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

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

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

%Y Column 1 of A235954.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 17 2014