A252226 Number of (n+2) X (6+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.

4738, 70284, 231254, 512822, 1339010, 4329476, 13842872, 42480650, 129860460, 399765942, 1232739446, 3797303378, 11691726372, 36003050792, 110877928074, 341465317292, 1051572312470, 3238405526966, 9972979227362, 30712764065540

Offset

1,1

Links

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

Formula

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

Empirical g.f.: 2*x*(2369 + 28035*x + 12570*x^2 - 62435*x^3 - 96634*x^4 - 37304*x^5 + 18124*x^6 + 13776*x^7) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - Colin Barker, Dec 02 2018

Example

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

Crossrefs

Column 6 of A252228.

Sequence in context: A234086 A093789 A357607 * A252204 A374502 A083637

Adjacent sequences: A252223 A252224 A252225 * A252227 A252228 A252229

Keyword

nonn

Author

R. H. Hardin, Dec 15 2014

Status

approved