A188825 Number of 3Xn binary arrays without the pattern 0 1 diagonally or antidiagonally.

8, 16, 48, 144, 432, 1296, 3888, 11664, 34992, 104976, 314928, 944784, 2834352, 8503056, 25509168, 76527504, 229582512, 688747536, 2066242608, 6198727824, 18596183472, 55788550416, 167365651248, 502096953744, 1506290861232

Offset: 1

Author

R. H. Hardin Apr 11 2011

Keywords

• nonn

Comments

Row 3 of A188824

Examples

			Some solutions for 3X3
..1..1..0....1..1..1....1..1..1....1..1..1....1..0..1....1..1..1....1..0..1
..0..0..1....1..1..0....1..1..1....0..0..0....0..1..0....1..1..0....0..1..0
..0..0..0....1..0..1....0..0..1....0..0..0....1..0..1....1..0..0....0..0..0
		

Formula

Empirical: a(n) = 3*a(n-1) for n>2