A228681 Number of n X 6 binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally.

21, 217, 2529, 28977, 333517, 3837761, 44171841, 508425617, 5852202757, 67361890809, 775372578689, 8924976046401, 102731553583965, 1182498825731233, 13611237290882689, 156673123529460833, 1803397245448244085

Offset: 1

Author

R. H. Hardin, Aug 30 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 6 of A228683.

Formula

Empirical: a(n) = 14*a(n-1) - 17*a(n-2) - 142*a(n-3) + 59*a(n-4) + 352*a(n-5) + 103*a(n-6) - 48*a(n-7).

Empirical g.f.: x*(21 - 77*x - 152*x^2 + 242*x^3 + 407*x^4 + 55*x^5 - 48*x^6) / (1 - 14*x + 17*x^2 + 142*x^3 - 59*x^4 - 352*x^5 - 103*x^6 + 48*x^7). - Colin Barker, Sep 12 2018