A252026 Number of (n+2)X(2+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 or 4

227, 323, 781, 1929, 5285, 14831, 41745, 117867, 332997, 941237, 2660915, 7523177, 21271317, 60144341, 170058799, 480846469, 1359611219, 3844354431, 10870074659, 30735606793, 86906264441, 245731273709, 694815999081, 1964622840375

Offset

1,1

Comments

Column 2 of A252032

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -a(n-2) +6*a(n-3) -12*a(n-4) -3*a(n-5) -a(n-6) +6*a(n-7) +a(n-8) +6*a(n-9) +a(n-10) +3*a(n-11) -3*a(n-12) -3*a(n-13) -2*a(n-14) for n>18

Example

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

Crossrefs

Sequence in context: A333425 A142261 A117458 * A210513 A142842 A142545

Adjacent sequences: A252023 A252024 A252025 * A252027 A252028 A252029

Keyword

nonn

Author

R. H. Hardin, Dec 12 2014

Status

approved