A167243 Number of ways to partition an n X 3 grid into 3 connected equal-area regions.

1, 3, 10, 23, 56, 132, 259, 546, 1095, 2043, 3908, 7379, 13208, 24194, 43819, 76790, 136489, 241311, 416152, 726073, 1261696, 2153026, 3706393, 6364842, 10775173, 18374181

Offset: 1

Author

R. H. Hardin, Oct 31 2009

Keywords

• nonn

Examples

			All solutions for n=4
...1.1.2...1.1.2...1.1.2...1.1.2...1.1.2...1.1.2...1.1.1...1.1.1...1.1.1
...1.2.2...1.2.2...1.1.2...1.1.2...1.3.2...3.1.2...1.2.2...1.2.2...1.2.2
...1.2.3...1.3.2...3.2.2...3.3.2...1.3.2...3.1.2...2.2.3...3.2.2...3.3.2
...3.3.3...3.3.3...3.3.3...3.3.2...3.3.2...3.3.2...3.3.3...3.3.3...3.3.2
------
...1.1.1...1.1.1...1.1.1...1.1.1...1.1.1...1.1.1...1.1.1...1.2.2...1.2.2
...1.2.3...2.2.1...2.2.1...2.2.1...2.1.3...2.1.3...2.3.1...1.2.2...1.2.2
...2.2.3...2.2.3...2.3.3...3.2.2...2.2.3...2.3.3...2.3.3...1.1.3...1.3.3
...2.3.3...3.3.3...2.3.3...3.3.3...2.3.3...2.2.3...2.2.3...3.3.3...1.3.3
------
...1.2.2...1.2.2...1.2.2...1.2.2...1.2.3
...1.2.3...1.1.2...1.1.2...1.3.2...1.2.3
...1.2.3...1.3.2...3.1.2...1.3.2...1.2.3
...1.3.3...3.3.3...3.3.3...1.3.3...1.2.3
		

Crossrefs

Cf. A167242.