A242470 Number of length n+2 0..7 arrays with no three equal elements in a row and new values 0..7 introduced in 0..7 order

4, 12, 41, 159, 685, 3233, 16533, 90817, 531812, 3295779, 21456363, 145645809, 1023308083, 7391587656, 54563960012, 409583330514, 3113836080693, 23899707589707, 184747234605277, 1435668152296255, 11200152289621048

Offset

1,1

Comments

Column 7 of A242472

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)

Example

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

Crossrefs

Sequence in context: A225586 A242468 A242469 * A242471 A239800 A237501

Adjacent sequences: A242467 A242468 A242469 * A242471 A242472 A242473

Keyword

nonn

Author

R. H. Hardin, May 15 2014

Status

approved