A184200 Number of (n+1) X 3 binary arrays with no 2 X 2 subblock containing fewer than two 1s.

35, 195, 1028, 5529, 29593, 158648, 850155, 4556371, 24418812, 130868377, 701364193, 3758831480, 20144755955, 107962068819, 578602594196, 3100912827657, 16618764665065, 89065173542888, 477328206813915

Offset: 1

Author

R. H. Hardin, Jan 10 2011

Keywords

• nonn

Comments

Column 2 of A184207.

Examples

			Some solutions for 5 X 3:
..0..1..1....1..1..0....1..1..0....1..1..1....0..1..0....0..0..1....1..1..0
..1..0..0....1..0..1....1..0..1....1..1..0....1..1..0....1..1..0....1..1..1
..0..1..1....0..1..1....1..1..0....1..0..1....1..1..1....0..1..1....1..1..0
..1..1..1....0..1..0....1..1..0....0..1..0....0..1..0....1..0..1....0..1..1
..0..1..1....0..1..1....1..0..1....0..1..0....1..1..1....1..0..1....1..0..0
		

Links

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

Crossrefs

Cf. A184207.

Formula

Empirical: a(n) = 5*a(n-1) + 4*a(n-2) - 11*a(n-3) - a(n-4) + 2*a(n-5).

Empirical g.f.: x*(35 + 20*x - 87*x^2 - 6*x^3 + 16*x^4) / (1 - 5*x - 4*x^2 + 11*x^3 + x^4 - 2*x^5). - Colin Barker, Feb 27 2018