A252248 Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 3 5 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 3 5 6 or 7.

260, 239, 242, 268, 302, 359, 437, 549, 707, 919, 1239, 1682, 2274, 3182, 4435, 6115, 8699, 12273, 17095, 24497, 34778, 48750, 70120, 99945, 140781, 202983, 290223, 410547, 593069, 850292, 1207544, 1747314, 2511473, 3579751, 5187795, 7474031

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 5*a(n-3) - 4*a(n-4) - 8*a(n-6) + 4*a(n-7) + 5*a(n-9) - a(n-10) -a(n-12) for n>16.

Empirical g.f.: x*(260 - 21*x + 3*x^2 - 1274*x^3 - 121*x^4 - 197*x^5 + 1786*x^6 + 546*x^7 + 551*x^8 - 661*x^9 - 268*x^10 - 203*x^11 + 47*x^12 + 30*x^13 + 8*x^14 + 4*x^15) / ((1 - x)*(1 + x + x^2)*(1 - x - x^3)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 02 2018

Example

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

Crossrefs

Column 2 of A252254.

Sequence in context: A121918 A097735 A063485 * A214471 A344238 A344237

Adjacent sequences: A252245 A252246 A252247 * A252249 A252250 A252251

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved