A186594 Number of (n+3)X7 0..3 arrays with every 4X4 subblock commuting with each horizontal and vertical neighbor 4X4 subblock

3306753, 104547, 407733, 2526165, 5080629, 5654805, 5711805, 5769381, 5831421, 5959701, 6475413, 9316941, 19268469, 36584472, 55233771, 81033246, 128348841, 198142701, 273483585, 378799581, 578518521, 897620265, 1289310978, 1848325452

Offset

1,1

Comments

Column 4 of A186599

Links

R. H. Hardin, Table of n, a(n) for n = 1..65

Formula

Empirical: a(n)=2*a(n-1)-a(n-2)+3*a(n-4)-6*a(n-5)+3*a(n-6)+3*a(n-8)-3*a(n-9) for n>14

Example

Some solutions for 5X7
..0..0..0..0..0..3..1....2..0..0..0..0..2..3....0..0..0..0..0..1..3
..0..0..0..0..0..1..3....0..0..0..0..0..0..0....0..0..0..0..0..0..3
..2..0..0..0..0..0..0....0..0..0..0..0..0..3....3..0..0..0..0..0..1
..3..0..0..0..0..0..0....0..0..0..0..0..0..0....2..0..0..0..0..0..0
..2..0..0..0..0..0..0....0..2..0..0..0..0..0....1..3..0..0..0..0..0

Crossrefs

Sequence in context: A206316 A186959 A369897 * A244574 A250675 A242608

Adjacent sequences: A186591 A186592 A186593 * A186595 A186596 A186597

Keyword

nonn

Author

R. H. Hardin Feb 24 2011

Status

approved