A220250 Sum of neighbor maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to the sum mod 3 of their king-move neighbors in a random 0..2 nX2 array.

2, 16, 48, 256, 928, 4096, 15872, 65536, 259584, 1048576, 4182016, 16777216, 67051520, 268435456, 1073479680, 4294967296, 17178689536, 68719476736, 274872664064, 1099511627776, 4398023442432, 17592186044416, 70368643514368

Offset: 1

Author

R. H. Hardin Dec 08 2012

Keywords

• nonn

Comments

Column 2 of A220254

Examples

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

Links

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

Formula

Empirical: a(n)=4*a(n-1)+8*a(n-2)-32*a(n-3)-16*a(n-4)+64*a(n-5)

a(n) = 4^n - 2^(n-2)*(n+1)*(1-(-1)^n). - Vaclav Kotesovec, Jul 06 2013