A208692 Number of 6 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 0 1 vertically.

21, 441, 1113, 11067, 41013, 301035, 1346961, 8556723, 42184905, 249260739, 1292345649, 7358809899, 39164938617, 218805732243, 1180444035057, 6530395532955, 35479909625769, 195286010577987, 1064871399311265

Offset: 1

Author

R. H. Hardin, Mar 01 2012

Keywords

• nonn

Comments

Row 6 of A208688.

Examples

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

Links

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

Crossrefs

Cf. A208688.

Formula

Empirical: a(n) = a(n-1) + 26*a(n-2) + 6*a(n-3) - 78*a(n-4).

Empirical g.f.: 21*x*(1 + 20*x + 6*x^2 - 78*x^3) / (1 - x - 26*x^2 - 6*x^3 + 78*x^4). - Colin Barker, Jul 05 2018