A250083 Number of length 2+5 0..n arrays with every six consecutive terms having the maximum of some two terms equal to the minimum of the remaining four terms.

83, 982, 5604, 21405, 63611, 159278, 352192, 708609, 1323835, 2329646, 3902548, 6272877, 9734739, 14656790, 21493856, 30799393, 43238787, 59603494, 80826020, 107995741, 142375563, 185419422, 238790624, 304381025, 384331051, 481050558

Offset

1,1

Links

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

Formula

Empirical: a(n) = (7/6)*n^6 + (28/3)*n^5 + (245/12)*n^4 + (47/2)*n^3 + (227/12)*n^2 + (26/3)*n + 1.

Conjectures from Colin Barker, Nov 11 2018: (Start)

G.f.: x*(83 + 401*x + 473*x^2 - 106*x^3 - 5*x^4 - 7*x^5 + x^6) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.

(End)

Example

Some solutions for n=6:
..4....4....1....2....4....0....4....4....2....1....4....3....1....4....4....0
..0....2....6....4....0....5....6....6....1....2....6....4....5....0....0....3
..0....1....2....6....2....2....4....5....3....5....1....1....5....0....3....5
..0....0....4....6....2....3....0....3....2....2....1....3....2....6....3....2
..3....3....2....1....2....2....5....1....5....5....1....1....4....0....5....2
..6....1....5....2....5....3....4....3....2....5....4....1....2....2....5....2
..3....3....0....2....3....0....4....6....4....0....2....4....2....4....3....1

Crossrefs

Row 2 of A250081.

Sequence in context: A112766 A128950 A068851 * A292284 A195893 A233332

Adjacent sequences: A250080 A250081 A250082 * A250084 A250085 A250086

Keyword

nonn

Author

R. H. Hardin, Nov 11 2014

Status

approved