A220748 Equals one maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal and vertical neighbors in a random 0..3 nX3 array

4, 38, 395, 3778, 32178, 261356, 2096110, 16776148, 134216342, 1073740504, 8589932829, 68719475152, 549755811711, 4398046509244, 35184372086204, 281474976708508, 2251799813682132, 18014398509479536, 144115188075852231

Offset

1,1

Comments

Column 3 of A220751

Links

R. H. Hardin, Table of n, a(n) for n = 1..59

Formula

Empirical: a(n) = 8*a(n-1) +3*a(n-2) -24*a(n-3) -3*a(n-4) +24*a(n-5) +a(n-6) -8*a(n-7) for n>14

Example

Some solutions for n=3
..0..1..1....1..1..1....0..1..1....0..0..0....0..1..0....0..1..0....0..0..1
..0..0..0....1..1..0....1..0..1....1..1..0....0..0..0....0..1..0....0..0..0
..0..0..0....0..0..1....0..1..0....0..1..1....1..0..0....1..0..1....0..1..1

Crossrefs

Sequence in context: A221021 A155859 A220543 * A192947 A234463 A194044

Adjacent sequences: A220745 A220746 A220747 * A220749 A220750 A220751

Keyword

nonn

Author

R. H. Hardin Dec 18 2012

Status

approved