A252069 Number of (n+2) X (2+2) 0..2 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 or 4.

105, 152, 419, 1135, 3029, 8352, 23091, 63460, 174704, 481577, 1326679, 3654425, 10068184, 27738117, 76416462, 210524456, 579990085, 1597852627, 4402027937, 12127445290, 33410714339, 92045405682, 253582052742, 698610194521

Offset

1,1

Comments

Column 2 of A252075.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + a(n-2) + 4*a(n-3) - a(n-4) - 4*a(n-5) - 3*a(n-6) + a(n-8) + a(n-9) for n>11.

Empirical g.f.: x*(105 - 58*x + 10*x^2 - 275*x^3 - 163*x^4 + 55*x^5 + 160*x^6 + 77*x^7 + 6*x^8 - 39*x^9 - 4*x^10) / ((1 - x)*(1 - x - 2*x^2 - 6*x^3 - 5*x^4 - x^5 + 2*x^6 + 2*x^7 + x^8)). - Colin Barker, Mar 20 2018

Example

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

Crossrefs

Cf. A252075.

Sequence in context: A069702 A239589 A203614 * A133509 A013590 A216918

Adjacent sequences: A252066 A252067 A252068 * A252070 A252071 A252072

Keyword

nonn

Author

R. H. Hardin, Dec 13 2014

Status

approved