A240515 Number of nX4 0..1 arrays with no element equal to exactly two horizontal and vertical neighbors, with new values 0..1 introduced in row major order.

5, 10, 28, 99, 326, 1080, 3765, 13282, 46928, 166611, 595402, 2132856, 7647821, 27453594, 98644580, 354622219, 1275200926, 4586567656, 16499401997, 59359672578, 213570572184, 768440651027, 2764982991218, 9949082534056

Offset: 1

Author

R. H. Hardin, Apr 06 2014

Keywords

• nonn

Comments

Column 4 of A240519

Examples

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

Links

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

Formula

Empirical: a(n) = 5*a(n-1) -5*a(n-2) +4*a(n-3) -3*a(n-4) -49*a(n-5) +10*a(n-6) +15*a(n-7) +45*a(n-8) +124*a(n-9) +131*a(n-10) +301*a(n-11) +18*a(n-12) -615*a(n-13) -201*a(n-14) -1508*a(n-15) -823*a(n-16) -413*a(n-17) -254*a(n-18) +2467*a(n-19) +793*a(n-20) +4516*a(n-21) +1071*a(n-22) +2289*a(n-23) -2289*a(n-25) -1071*a(n-26) -4516*a(n-27) -793*a(n-28) -2467*a(n-29) +254*a(n-30) +413*a(n-31) +823*a(n-32) +1508*a(n-33) +201*a(n-34) +615*a(n-35) -18*a(n-36) -301*a(n-37) -131*a(n-38) -124*a(n-39) -45*a(n-40) -15*a(n-41) -10*a(n-42) +49*a(n-43) +3*a(n-44) -4*a(n-45) +5*a(n-46) -5*a(n-47) +a(n-48)