A230703 Number of (n+3) X (3+3) 0..2 white square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero.

30, 244, 2106, 16536, 130446, 1025430, 8053490, 63237238, 496590056, 3899177780, 30617038898, 240407287782, 1887698838680, 14822368917190, 116386479715646, 913876264039036, 7175832414626878, 56345230976142602, 442427428831168274

Offset: 1

Author

R. H. Hardin, Oct 28 2013

Keywords

• nonn

Comments

Column 3 of A230708.

Examples

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

Links

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

Crossrefs

Cf. A230708.

Formula

Empirical: a(n) = 6*a(n-1) +27*a(n-2) -64*a(n-3) -295*a(n-4) -13*a(n-5) +1890*a(n-6) +812*a(n-7) -4466*a(n-8) -467*a(n-9) -3948*a(n-10) +16934*a(n-11) -22529*a(n-12) +17109*a(n-13) -1911*a(n-14) -6225*a(n-15) +731*a(n-16) +3024*a(n-17) -978*a(n-18) -86*a(n-19) +436*a(n-20) -24*a(n-21) -30*a(n-22).