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

1,1

Comments

Row 3 of A188824

Links

Table of n, a(n) for n=1..25.

Formula

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

Example

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

Crossrefs

Sequence in context: A022444 A089828 A297619 * A214204 A335771 A159038

Adjacent sequences: A188822 A188823 A188824 * A188826 A188827 A188828

Keyword

nonn

Author

R. H. Hardin Apr 11 2011

Status

approved