A231741 Number of nX2 0..3 arrays with no element less than a strict majority of its horizontal and vertical neighbors.

4, 84, 318, 1328, 6064, 26918, 116909, 511264, 2248196, 9868600, 43259517, 189716276, 832295019, 3650903623, 16013507645, 70240174360, 308101760364, 1351448959786, 5927927566218, 26002016887928, 114054342072628

Offset: 1

Author

R. H. Hardin, Nov 13 2013

Keywords

• nonn

Comments

Column 2 of A231746

Examples

			Some solutions for n=7
..0..2....1..2....2..0....0..0....2..1....2..1....1..1....2..0....2..0....0..1
..0..2....1..1....3..0....2..2....1..1....2..1....0..0....0..0....1..0....0..2
..0..3....1..1....1..0....2..3....1..1....0..0....0..0....0..0....0..0....0..3
..0..3....3..3....0..0....0..0....1..1....0..0....1..2....2..2....0..0....0..0
..0..2....0..0....0..0....0..0....2..2....1..0....1..1....3..3....0..0....0..0
..0..0....0..0....3..2....1..1....2..2....3..0....3..1....0..0....2..2....0..0
..3..0....2..0....2..2....1..2....3..3....3..0....0..0....0..0....2..3....3..0
		

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -39*a(n-2) +104*a(n-3) -251*a(n-4) +391*a(n-5) -483*a(n-6) +687*a(n-7) -378*a(n-8) +503*a(n-9) -247*a(n-10) -66*a(n-11) -292*a(n-12) -300*a(n-13) -217*a(n-14) -153*a(n-15) -70*a(n-16) -27*a(n-17) -8*a(n-18) -a(n-19) for n>20