A249711 Number of length 5+3 0..n arrays with every four consecutive terms having the maximum of some two terms equal to the minimum of the remaining two terms.

38, 377, 1724, 5425, 13666, 29673, 57912, 104289, 176350, 283481, 437108, 650897, 940954, 1326025, 1827696, 2470593, 3282582, 4294969, 5542700, 7064561, 8903378, 11106217, 13724584, 16814625, 20437326, 24658713, 29550052, 35188049, 41655050

Offset

1,1

Links

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

Formula

Empirical: a(n) = (5/3)*n^5 + 10*n^4 + 16*n^3 + 8*n^2 + (4/3)*n + 1.

Conjectures from Colin Barker, Nov 10 2018: (Start)

G.f.: x*(38 + 149*x + 32*x^2 - 24*x^3 + 6*x^4 - x^5) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

Example

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

Crossrefs

Row 5 of A249707.

Sequence in context: A201244 A240263 A156661 * A220918 A187078 A155193

Adjacent sequences: A249708 A249709 A249710 * A249712 A249713 A249714

Keyword

nonn

Author

R. H. Hardin, Nov 04 2014

Status

approved