A263054 Number of (n+1) X (2+1) 0..1 arrays with each row and column not divisible by 3, read as a binary number with top and left being the most significant bits.

2, 33, 142, 895, 4314, 22921, 113486, 577071, 2877562, 14455993, 72225582, 361607935, 1807659674, 9041669481, 45205690126, 226052092111, 1130241870522, 5651375017753, 28256745002222, 141284885366175, 706423516399834

Offset: 1

Author

R. H. Hardin, Oct 08 2015

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A263060.

Formula

Empirical: a(n) = 5*a(n-1) + 12*a(n-2) - 60*a(n-3) - 39*a(n-4) + 195*a(n-5) + 28*a(n-6) - 140*a(n-7).

Empirical g.f.: x*(2 + 23*x - 47*x^2 - 91*x^3 + 193*x^4 + 28*x^5 - 140*x^6) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 5*x)*(1 - 7*x^2)). - Colin Barker, Jan 01 2019