A252227 Number of (n+2) X (7+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.

9922, 219824, 718514, 1619714, 4297634, 13842872, 44099648, 135348914, 414030384, 1274652450, 3930132146, 12105939362, 37274285880, 114781892768, 353490924114, 1088626770704, 3352521852434, 10324377012002, 31794906089378

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*(4961 + 95029*x + 34482*x^2 - 172885*x^3 - 266116*x^4 - 117704*x^5 + 41864*x^6 + 39568*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=1:
..1..0..2..0..1..1..2..0..1....1..0..2..0..2..0..1..1..1
..0..2..0..2..0..2..0..2..2....0..2..0..2..0..2..0..2..1
..2..0..2..0..1..1..2..0..1....1..1..2..0..2..0..2..0..2

Crossrefs

Column 7 of A252228.

Sequence in context: A072848 A145381 A212401 * A252622 A031856 A252573

Adjacent sequences: A252224 A252225 A252226 * A252228 A252229 A252230

Keyword

nonn

Author

R. H. Hardin, Dec 15 2014

Status

approved