A230660 Number of nX7 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j).

0, 63, 1155, 11745, 477279, 3951657, 169006665, 1374288243, 59075291211, 479621050353, 20625942501183, 167435671598913, 7200781142959245, 58453268091967479, 2513864130034802115, 20406595554618417837

Offset: 1

Author

R. H. Hardin, Oct 27 2013

Keywords

• nonn

Comments

Column 7 of A230661

Examples

			Some solutions for n=5
..x..0..x..1..x..2..x....x..0..x..1..x..1..x....x..0..x..0..x..0..x
..2..x..0..x..1..x..0....0..x..2..x..1..x..1....0..x..2..x..2..x..0
..x..1..x..2..x..2..x....x..2..x..1..x..0..x....x..2..x..2..x..2..x
..0..x..1..x..2..x..0....0..x..1..x..2..x..1....2..x..0..x..2..x..1
..x..2..x..1..x..0..x....x..2..x..0..x..1..x....x..0..x..0..x..1..x
		

Links

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

Formula

Empirical: a(n) = 390*a(n-2) -14687*a(n-4) +146138*a(n-6) -823339*a(n-8) -2774563*a(n-10) [phone]*a(n-12) -60400888*a(n-14) [phone]*a(n-16) -35490451*a(n-18) -7548040169*a(n-20) [phone]*a(n-22) [phone]*a(n-24) [phone]*a(n-26) [phone]*a(n-28) [phone]*a(n-30) [phone]*a(n-32) [phone]*a(n-34) [phone]*a(n-36) -5387877662*a(n-38) [phone]*a(n-40) -121037200*a(n-42) [phone]*a(n-44) +414720*a(n-46) for n>47