A252262 Number of (n+2) X (1+2) 0..3 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 2 3 4 6 or 7.

103, 130, 258, 598, 1342, 2900, 6330, 14024, 31000, 68154, 149830, 330046, 727264, 1601418, 3525492, 7763096, 17096250, 37647546, 82899002, 182544940, 401975946, 885174328, 1949187840, 4292186538, 9451591070, 20812845566, 45830805744

Offset

1,1

Links

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

Formula

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

Empirical g.f.: x*(103 + 27*x + 128*x^2 + 31*x^3 - 58*x^4 - 148*x^5 - 122*x^6 - 16*x^7) / (1 - x - 3*x^3 - 4*x^4 - 4*x^5 - 2*x^6). - Colin Barker, Dec 03 2018

Example

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

Crossrefs

Column 1 of A252269.

Sequence in context: A139979 A146357 A252269 * A023080 A219785 A129484

Adjacent sequences: A252259 A252260 A252261 * A252263 A252264 A252265

Keyword

nonn

Author

R. H. Hardin, Dec 16 2014

Status

approved