A240644 Number of nX3 0..1 arrays with no element equal to the same number of vertical neighbors as horizontal neighbors, with new values 0..1 introduced in row major order.

1, 2, 6, 8, 23, 60, 149, 396, 1050, 2814, 7571, 20372, 54879, 147946, 399002, 1076312, 2903613, 7833652, 21135287, 57024772, 153859830, 415135862, 1120101045, 3022215348, 8154444873, 22002086130, 59365425382, 160178219728, 432188727639

Offset: 1

Author

R. H. Hardin, Apr 09 2014

Keywords

• nonn

Comments

Column 3 of A240649

Examples

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

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -3*a(n-2) -2*a(n-3) +2*a(n-4) +2*a(n-5) -7*a(n-6) -8*a(n-7) +15*a(n-8) +4*a(n-9) -8*a(n-10) -4*a(n-11) +15*a(n-12) +8*a(n-13) -7*a(n-14) -2*a(n-15) +2*a(n-16) +2*a(n-17) -3*a(n-18) -4*a(n-19) -a(n-20)