A240279 Number of nX2 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.

2, 8, 19, 38, 114, 251, 612, 1656, 3758, 9630, 24258, 57548, 146898, 360946, 880960, 2217967, 5429271, 13419200, 33424298, 82079277, 203571196, 504206276, 1242741927, 3081338174, 7616293969, 18815746878, 46600839533, 115150972966

Offset: 1

Author

R. H. Hardin, Apr 03 2014

Keywords

• nonn

Comments

Column 2 of A240284

Examples

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

Links

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

Formula

Empirical: a(n) = 3*a(n-2) +10*a(n-3) -3*a(n-4) -6*a(n-5) -3*a(n-6) +8*a(n-7) -7*a(n-8) -9*a(n-9) -4*a(n-10) +13*a(n-11) -14*a(n-12) +17*a(n-13) -a(n-15)