A251772 Number of (n+2) X (1+2) 0..3 arrays with every 3 X 3 subblock row and column sum 3 or 6 and every diagonal and antidiagonal sum not 3 or 6.

470, 1142, 2402, 4790, 12302, 27242, 55766, 148022, 332738, 688646, 1847582, 4175018, 8671142, 23345702, 52842914, 109873622, 296146862, 670682474, 1395012278, 3761354582, 8519745410, 17722964198, 47791500542, 108256965290

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 16*a(n-3) - 16*a(n-4) - 39*a(n-6) + 39*a(n-7) - 36*a(n-9) + 36*a(n-10).

Empirical g.f.: 2*x*(235 + 336*x + 630*x^2 - 2566*x^3 - 1620*x^4 - 2610*x^5 + 4323*x^6 - 864*x^7 - 2592*x^8 + 4788*x^9) / ((1 - x)*(1 - 4*x^3)*(1 - 12*x^3 - 9*x^6)). - Colin Barker, Nov 30 2018

Example

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

Crossrefs

Column 1 of A251779.

Sequence in context: A277119 A104744 A251779 * A253518 A254423 A254416

Adjacent sequences: A251769 A251770 A251771 * A251773 A251774 A251775

Keyword

nonn

Author

R. H. Hardin, Dec 08 2014

Status

approved