A184469 1/6 the number of (n+2) X 3 0..2 arrays with each 3 X 3 subblock containing one of one value, four of another, and four of the last.

315, 1095, 3705, 12339, 45585, 161739, 559305, 2147931, 7836561, 27667251, 108488889, 401513355, 1432182465, 5674143555, 21145265865, 75792359259, 301775575185, 1128283339059, 4053433203225, 16177609637451, 60579025906401

Offset: 1

Author

R. H. Hardin, Jan 15 2011

Keywords

• nonn

Comments

Column 1 of A184477.

Examples

			Some solutions with a(1,1)=0 for 4 X 3:
..0..2..2....0..1..2....0..2..0....0..0..2....0..1..2....0..1..2....0..2..1
..2..0..1....1..2..1....0..2..0....2..0..2....1..2..1....0..2..0....1..1..2
..0..2..0....2..1..2....2..1..2....2..1..0....2..1..2....2..2..0....1..2..2
..0..2..2....2..0..1....0..2..0....0..0..2....1..0..2....0..1..2....2..0..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A184477.

Formula

Empirical: a(n) = 3*a(n-1) + 96*a(n-3) - 288*a(n-4) - 2700*a(n-6) + 8100*a(n-7) + 23328*a(n-9) - 69984*a(n-10).

Empirical g.f.: 3*x*(105 + 50*x + 140*x^2 - 9672*x^3 - 1944*x^4 - 5112*x^5 + 269028*x^6 + 17496*x^7 + 42768*x^8 - 2332800*x^9) / ((1 - 3*x)*(1 - 18*x^3)*(1 - 24*x^3)*(1 - 54*x^3)). - Colin Barker, Apr 12 2018