A167240 Number of ways to partition a 3*n X 2 grid into 6 connected equal-area regions

1, 13, 41, 169, 441, 1109, 2289, 4497, 7953, 13533, 21593, 33465, 49673, 72101, 101473, 140321, 189601

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Example

Some solutions for n=4
...1.1...1.2...1.1...1.1...1.1...1.1...1.2...1.1...1.1...1.1...1.1...1.1...1.1
...1.2...1.2...1.2...1.2...1.2...1.2...1.2...1.1...1.2...1.1...1.1...2.1...2.1
...1.2...1.2...1.2...1.2...1.2...1.2...1.2...2.2...1.2...2.2...2.2...2.1...2.1
...3.2...1.2...2.2...2.2...3.2...2.2...1.2...3.2...2.2...2.3...2.3...2.3...2.2
...3.2...3.3...3.3...3.3...3.2...3.3...3.4...3.2...3.3...2.3...2.3...2.3...3.3
...3.3...3.3...3.4...4.3...3.4...3.3...3.4...3.4...3.3...3.3...3.3...3.3...4.3
...4.4...4.4...3.4...4.3...3.4...4.4...3.4...3.4...4.4...4.4...4.4...4.4...4.3
...5.4...5.4...5.4...4.4...4.4...4.4...3.4...4.4...4.5...4.4...4.4...4.4...4.4
...5.4...5.4...5.4...5.6...5.5...5.5...5.5...5.5...4.5...5.5...5.6...5.5...5.5
...5.6...5.5...5.6...5.6...5.6...5.6...6.5...6.5...6.5...5.5...5.6...5.5...5.5
...5.6...6.6...5.6...5.6...5.6...5.6...6.5...6.5...6.5...6.6...5.6...6.6...6.6
...6.6...6.6...6.6...5.6...6.6...6.6...6.6...6.6...6.6...6.6...5.6...6.6...6.6

Crossrefs

Sequence in context: A305155 A355965 A231885 * A147247 A028468 A146995

Adjacent sequences: A167237 A167238 A167239 * A167241 A167242 A167243

Keyword

nonn

Author

R. H. Hardin Oct 31 2009

Status

approved