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

1,2

Comments

Column 7 of A212829

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

Example

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

Crossrefs

Sequence in context: A212825 A212826 A212827 * A212830 A000719 A149875

Adjacent sequences: A212825 A212826 A212827 * A212829 A212830 A212831

Keyword

nonn

Author

R. H. Hardin May 28 2012

Status

approved