A250064 Number of length 4+6 0..n arrays with no seven consecutive terms having the maximum of any two terms equal to the minimum of the remaining five terms.

21, 4030, 132054, 1800040, 14492075, 82072086, 361440380, 1318262304, 4153110705, 11640299550, 29654571826, 69781269480, 153557285479, 319076606870, 630919231800, 1194629311616, 2177281160205, 3836033915454

Offset

1,1

Comments

Row 4 of A250059.

Links

R. H. Hardin, Table of n, a(n) for n = 1..185

Formula

Empirical: a(n) = n^10 + n^9 + (40/7)*n^8 + 7*n^7 - (11/6)*n^6 + (20/3)*n^5 + (25/6)*n^4 - (25/6)*n^3 + (61/42)*n^2.

Conjectures from Colin Barker, Aug 22 2017: (Start)

G.f.: x*(21 + 3799*x + 88879*x^2 + 565631*x^3 + 1296585*x^4 + 1192749*x^5 + 430621*x^6 + 49661*x^7 + 854*x^8) / (1 - x)^11.

a(n) = 11*a(n-1) - 55*a(n-2) + 165*a(n-3) - 330*a(n-4) + 462*a(n-5) - 462*a(n-6) + 330*a(n-7) - 165*a(n-8) + 55*a(n-9) - 11*a(n-10) + a(n-11) for n>11.

(End)

Example

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

Crossrefs

Sequence in context: A153833 A221164 A264250 * A200998 A209473 A055416

Adjacent sequences: A250061 A250062 A250063 * A250065 A250066 A250067

Keyword

nonn

Author

R. H. Hardin, Nov 11 2014

Status

approved