A232156 Number of nX3 0..3 arrays with every 0 next to a 1, every 1 next to a 2 and every 2 next to a 3 horizontally, vertically or antidiagonally, and no adjacent values equal.

4, 62, 290, 1284, 5902, 27086, 124436, 572080, 2629946, 12090710, 55591878, 255589946, 1175154022, 5403111082, 24842308392, 114220099740, 525160514282, 2414582116408, 11101765510580, 51043677955498, 234688597761528

Offset: 1

Author

R. H. Hardin, Nov 19 2013

Keywords

• nonn

Comments

Column 3 of A232161

Examples

			Some solutions for n=7
..1..2..3....1..2..3....0..1..2....1..2..3....2..1..0....0..3..1....2..1..2
..3..1..0....3..1..2....2..0..3....3..0..1....3..2..1....1..2..0....3..0..3
..0..3..2....2..0..3....3..2..1....1..2..0....1..0..2....0..3..2....1..2..1
..2..0..1....3..1..2....1..0..3....0..3..2....2..3..0....2..0..3....3..0..2
..1..3..0....2..3..0....3..2..1....2..0..3....1..2..1....1..2..0....2..3..0
..0..2..1....1..2..1....0..3..0....3..1..2....0..3..0....3..1..3....0..1..2
..3..0..3....0..3..0....1..2..1....0..3..1....2..1..3....2..0..2....2..3..1
		

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -12*a(n-2) -33*a(n-3) +40*a(n-4) +286*a(n-5) -545*a(n-6) -642*a(n-7) +2651*a(n-8) -1783*a(n-9) -2378*a(n-10) +4407*a(n-11) -1301*a(n-12) -2857*a(n-13) +3373*a(n-14) +157*a(n-15) -2558*a(n-16) +366*a(n-17) +1084*a(n-18) +818*a(n-19) -2988*a(n-20) -2028*a(n-21) +2529*a(n-22) +1294*a(n-23) +328*a(n-24) +582*a(n-25) -122*a(n-26) -180*a(n-27) +47*a(n-28) +21*a(n-29) -3*a(n-30) for n>33