A246001 Number of length 6+2 0..n arrays with no pair in any consecutive three terms totalling exactly n.

2, 56, 2308, 23168, 171942, 795144, 3057032, 9401216, 25819210, 62402840, 139927692, 288998016, 566057198, 1047126248, 1862251792, 3175741184, 5253738642, 8416795896, 13163097620, 20070807680, 30009814582, 43960191176

Offset

1,1

Comments

Row 6 of A245995.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +3*a(n-2) -17*a(n-3) +3*a(n-4) +39*a(n-5) -25*a(n-6) -45*a(n-7) +45*a(n-8) +25*a(n-9) -39*a(n-10) -3*a(n-11) +17*a(n-12) -3*a(n-13) -3*a(n-14) +a(n-15).

Example

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

Crossrefs

Cf. A245995.

Sequence in context: A224297 A193476 A193475 * A009555 A054959 A206305

Adjacent sequences: A245998 A245999 A246000 * A246002 A246003 A246004

Keyword

nonn

Author

R. H. Hardin, Aug 09 2014

Status

approved