A212828 Number of 0..7 arrays of length n with no adjacent pair equal to its immediately preceding adjacent pair, and new values introduced in 0..7 order.

1, 2, 5, 13, 44, 168, 717, 3360, 17091, 93492, 545670, 3372738, 21911216, 148486735, 1041923520, 7518618028, 55460237723, 416078640459, 3161904730760, 24261222270154, 187499556005523, 1456815538485716, 11363752138036864

Offset: 1

Author

R. H. Hardin May 28 2012

Keywords

• nonn

Comments

Column 7 of A212829

Examples

			Some solutions for n=8
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....0....1....1....1....1....1....1....1....1....1....1....1....0....0....1
..2....1....2....2....2....0....1....0....2....1....1....2....2....1....1....1
..2....1....1....0....2....2....2....2....3....0....0....3....3....2....2....2
..3....1....3....1....0....0....1....3....2....1....2....3....0....1....1....1
..4....2....2....2....2....3....3....0....4....2....1....0....1....1....1....1
..3....3....4....1....1....3....4....0....1....1....0....1....4....1....3....2
..5....0....4....0....0....4....4....0....4....0....0....3....4....3....0....2
		

Links

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

Formula

Empirical: a(n) = 22*a(n-1) -168*a(n-2) +440*a(n-3) +421*a(n-4) -2898*a(n-5) -924*a(n-6) +7944*a(n-7) +5931*a(n-8) -6610*a(n-9) -10562*a(n-10) -5040*a(n-11) -840*a(n-12) for n>15