A239594 Number of n X 2 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.

4, 3, 4, 4, 5, 7, 8, 11, 12, 16, 19, 24, 30, 36, 46, 55, 70, 85, 106, 131, 161, 201, 246, 307, 377, 468, 578, 714, 885, 1091, 1353, 1669, 2067, 2554, 3158, 3907, 4827, 5974, 7381, 9132, 11288, 13959, 17262, 21340, 26394, 32628, 40353, 49890, 61693, 76284, 94321

Offset: 1

Author

R. H. Hardin, Mar 22 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A239599.

Formula

Empirical: a(n) = a(n-2) + a(n-5) for n>6.

Empirical g.f.: x*(4 + 3*x + x^3 + x^4 - x^5) / (1 - x^2 - x^5). - Colin Barker, Oct 26 2018