A183665 - OEIS

%I #9 Apr 02 2018 13:02:00

%S 1225,5215,24745,126223,678265,3791935,21874825,129463663,782782105,

%T 4819857055,30146536105,191148081103,1226597365945,7954555064575,

%U 52068989200585,343658085034543,2284795961645785,15288911173702495

%N Number of (n+1) X 3 0..6 arrays with every 2 X 2 subblock summing to 12.

%C Column 2 of A183672.

%H R. H. Hardin, <a href="/A183665/b183665.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 28*a(n-1) - 322*a(n-2) + 1960*a(n-3) - 6769*a(n-4) + 13132*a(n-5) - 13068*a(n-6) + 5040*a(n-7).

%F Empirical g.f.: x*(1225 - 29085*x + 273175*x^2 - 1288407*x^3 + 3182536*x^4 - 3842244*x^5 + 1728720*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 7*x)). - _Colin Barker_, Apr 02 2018

%e Some solutions for 5 X 3:

%e ..2..6..2....1..3..2....4..3..4....0..4..0....3..3..3....3..2..2....0..6..2

%e ..4..0..4....4..4..3....3..2..3....3..5..3....6..0..6....3..4..4....2..4..0

%e ..6..2..6....2..2..3....3..4..3....3..1..3....1..5..1....5..0..4....2..4..4

%e ..1..3..1....5..3..4....2..3..2....6..2..6....2..4..2....5..2..6....6..0..4

%e ..5..3..5....2..2..3....3..4..3....0..4..0....1..5..1....3..2..2....4..2..6

%Y Cf. A183672.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 06 2011