A221021 Equals one maps: number of nX3 binary arrays indicating the locations of corresponding elements equal to exactly one of their horizontal, vertical and antidiagonal neighbors in a random 0..3 nX3 array

4, 38, 371, 3474, 30167, 251674, 2055232, 16609480, 133546783, 1071058030, 8579199454, 68676536212, 549584051869, 4397359463098, 35181623896924, 281463983943136, 2251755842615323, 18014222625202438, 144114484538737882

Offset

1,1

Comments

Column 3 of A221024

Links

R. H. Hardin, Table of n, a(n) for n = 1..87

Formula

Empirical: a(n) = 12*a(n-1) -30*a(n-2) -24*a(n-3) +63*a(n-4) +12*a(n-5) -32*a(n-6) for n>11

Example

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

Crossrefs

Sequence in context: A020865 A240378 A220807 * A155859 A220543 A220748

Adjacent sequences: A221018 A221019 A221020 * A221022 A221023 A221024

Keyword

nonn

Author

R. H. Hardin Dec 28 2012

Status

approved