A209521 Number of nX2 0..7 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..7 introduced in row major order.

2, 6, 57, 700, 10677, 193676, 4054358, 95534880, 2472405340, 68613576496, 1999809519672, 60231323048000, 1853103730499696, 57790053276242496, 1817609007303894496, 57472115932658904064, 1823283879810883824576

Offset: 1

Author

R. H. Hardin Mar 10 2012

Keywords

• nonn

Comments

Column 2 of A209527

Examples

			Some solutions for n=5
..0..0....0..0....0..0....0..0....0..0....0..0....0..1....0..0....0..0....0..0
..1..2....1..2....1..2....1..2....1..2....1..2....0..2....1..2....1..2....1..2
..0..1....0..1....0..2....0..0....0..0....1..3....0..1....0..0....0..0....1..3
..2..0....0..2....3..0....3..4....1..2....0..3....3..3....1..2....2..3....0..0
..0..1....1..0....0..1....0..3....2..0....3..4....2..0....0..0....0..0....1..2
		

Links

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

Formula

Empirical: a(n) = 68*a(n-1) -1410*a(n-2) +5696*a(n-3) +105944*a(n-4) -757536*a(n-5) -1207008*a(n-6) +7568640*a(n-7) [phone]*a(n-8) +4354560*a(n-9) for n>10