A252068 Number of (n+2)X(1+2) 0..2 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 3 or 4.

92, 105, 183, 375, 767, 1573, 3279, 6994, 15046, 32452, 70313, 153169, 334742, 732720, 1606016, 3524854, 7743783, 17022376, 37434303, 82351952, 181216059, 398841171, 877929646, 1932693875, 4255002737, 9368295558, 20627108406

Offset: 1

Author

R. H. Hardin, Dec 13 2014

Keywords

• nonn

Comments

Column 1 of A252075

Examples

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

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +2*a(n-3) +2*a(n-4) -5*a(n-5) -6*a(n-6) -8*a(n-7) -3*a(n-8) +3*a(n-9) +6*a(n-10) +6*a(n-11) +2*a(n-12) for n>14