A252259 Number of (n+2) X (3+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 2 3 6 or 7.

965, 562, 596, 778, 1260, 1636, 2478, 3940, 5958, 9178, 14534, 22666, 35250, 55690, 88338, 138082, 217874, 348706, 546498, 861730, 1385538, 2174338, 3427394, 5523586, 8674050, 13670530, 22057218, 34649602, 54604034, 88154626, 138505218

Offset

1,1

Links

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

Formula

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

Empirical g.f.: x*(965 - 403*x + 34*x^2 - 5608*x^3 + 2900*x^4 + 172*x^5 + 7470*x^6 - 4654*x^7 + 34*x^8 - 376*x^9 + 440*x^10 - 968*x^11) / ((1 - x)*(1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 03 2018

Example

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

Crossrefs

Column 3 of A252260.

Sequence in context: A267973 A267996 A093232 * A225684 A186468 A345549

Adjacent sequences: A252256 A252257 A252258 * A252260 A252261 A252262

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved