A208711 Number of 4Xn 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

8, 128, 1372, 16084, 185344, 2142580, 24754628, 286034292, 3305009328, 38188137788, 441249345280, 5098468022268, 58910854227068, 680692462409636, 7865141904908344, 90878716312611076, 1050068921631026592

Offset: 1

Author

R. H. Hardin Mar 01 2012

Keywords

• nonn

Comments

Row 4 of A208709

Examples

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

Links

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

Formula

Empirical: a(n) = 9*a(n-1) +31*a(n-2) -11*a(n-3) -71*a(n-4) -a(n-5) +38*a(n-6) -8*a(n-7) for n>9