A252188 Number of (n+2) X (4+2) 0..3 arrays with every 3 X 3 subblock row and column sum equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum not equal to 0, 1, 3, 6, or 7.

3341, 3996, 5460, 9233, 14130, 21417, 34532, 55336, 84332, 135776, 218896, 334872, 539664, 871440, 1334792, 2152016, 3477712, 5329992, 8595024, 13894992, 21301832, 34354256, 55548496, 85171272, 137365584, 222131280, 340613192, 549359696, 888399952, 1362309192

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 7*a(n-3) -14*a(n-6) +8*a(n-9) for n>17.

Example

Some solutions for n=4:
..3..3..1..3..2..1....1..2..3..1..2..0....3..3..0..3..0..0....2..1..0..2..1..3
..0..1..2..0..1..2....2..1..0..2..1..0....2..1..0..2..1..3....2..2..3..1..2..0
..0..3..0..0..3..0....0..3..0..3..3..0....1..2..0..1..2..0....3..3..0..0..3..0
..3..2..1..3..2..1....1..2..0..1..2..0....0..3..0..3..3..0....2..1..0..2..1..0
..0..1..2..0..1..0....2..1..0..2..1..3....2..1..0..2..1..0....1..2..0..1..2..3
..0..3..0..0..3..0....3..3..0..3..0..3....1..2..3..1..2..0....0..3..0..3..3..0

Crossrefs

Column 4 of A252192.

Sequence in context: A261656 A231955 A255657 * A270338 A054356 A358312

Adjacent sequences: A252185 A252186 A252187 * A252189 A252190 A252191

Keyword

nonn

Author

R. H. Hardin, Dec 15 2014

Status

approved