A246002 Number of length 7+2 0..n arrays with no pair in any consecutive three terms totalling exactly n

2, 82, 5572, 75260, 728358, 4108062, 18838280, 66983128, 209732170, 567864650, 1413132492, 3203059092, 6839534702, 13687432150, 26203871248, 47834595632, 84386904210, 143553121218, 237664797140, 382348873900, 601693049782

Offset

1,1

Comments

Row 7 of A245995

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +4*a(n-2) -20*a(n-3) +56*a(n-5) -28*a(n-6) -84*a(n-7) +70*a(n-8) +70*a(n-9) -84*a(n-10) -28*a(n-11) +56*a(n-12) -20*a(n-14) +4*a(n-15) +3*a(n-16) -a(n-17)

Example

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

Crossrefs

Sequence in context: A332584 A197641 A093666 * A063270 A087617 A263365

Adjacent sequences: A245999 A246000 A246001 * A246003 A246004 A246005

Keyword

nonn

Author

R. H. Hardin, Aug 09 2014

Status

approved