A205250 Number of (n+1) X 4 0..1 arrays with the number of clockwise edge increases in every 2 X 2 subblock the same.

112, 752, 5212, 36304, 253072, 1764364, 12301024, 85762192, 597930556, 4168748272, 29064349264, 202635502636, 1412766774400, 9849754525648, 68672102130652, 478779201937552, 3338029812632080, 23272612897409356

Offset: 1

Author

R. H. Hardin, Jan 24 2012

Keywords

• nonn

Comments

Column 3 of A205255.

Examples

			Some solutions for n=4:
..0..0..1..1....0..1..1..1....1..0..1..1....1..1..0..1....1..1..0..1
..1..0..0..0....1..1..0..1....1..0..0..1....0..1..1..1....0..1..0..1
..0..0..1..1....1..0..0..1....1..1..1..1....1..1..0..0....1..1..0..1
..0..1..1..0....1..1..1..1....0..0..0..1....0..1..1..1....0..1..0..1
..1..1..0..0....1..0..0..1....0..1..0..1....0..0..1..0....1..1..0..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A205255.

Formula

Empirical: a(n) = 10*a(n-1) - 24*a(n-2) + 21*a(n-3) - 6*a(n-4).

Empirical g.f.: 4*x*(2 - 3*x)*(14 - 25*x + 10*x^2) / ((1 - x)*(1 - 9*x + 15*x^2 - 6*x^3)). - Colin Barker, Jun 11 2018