A183425 Half the number of n X 2 0..2 arrays with no element equal its row sum plus its column sum mod 3.

3, 9, 32, 129, 513, 2048, 8193, 32769, 131072, 524289, 2097153, 8388608, 33554433, 134217729, 536870912, 2147483649, 8589934593, 34359738368, 137438953473, 549755813889, 2199023255552, 8796093022209, 35184372088833, 140737488355328

Offset

1,1

Comments

Column 2 of A183429.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=4*a(n-1) + a(n-3) - 4*a(n-4).

Empirical g.f.: x*(3 - 3*x - 4*x^2 - 2*x^3) / ((1 - x)*(1 - 4*x)*(1 + x + x^2)). - Colin Barker, Mar 29 2018

Example

Some solutions for 4 X 2:
..1..2....2..2....0..1....2..1....0..2....1..1....0..0....2..1....1..1....0..2
..0..2....2..2....0..1....1..2....0..0....1..2....0..1....0..1....1..2....1..0
..1..2....2..2....0..1....1..2....1..2....0..2....0..0....2..2....2..2....0..0
..1..1....2..2....0..1....2..1....1..0....1..2....1..0....2..1....2..1....1..2

Crossrefs

Cf. A183429.

Sequence in context: A193621 A344623 A320180 * A039628 A194530 A324238

Adjacent sequences: A183422 A183423 A183424 * A183426 A183427 A183428

Keyword

nonn

Author

R. H. Hardin, Jan 04 2011

Status

approved