A267235 Number of length-6 0..n arrays with no following elements greater than or equal to the first repeated value.

8, 223, 1790, 8274, 27854, 76237, 180292, 382404, 745548, 1359083, 2345266, 3866486, 6133218, 9412697, 14038312, 20419720, 29053680, 40535607, 55571846, 74992666, 99765974, 131011749, 170017196, 218252620, 277388020, 349310403

Offset

1,1

Links

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

Formula

Empirical: a(n) = n^6 + (197/60)*n^5 + 3*n^4 + (3/4)*n^3 - (1/30)*n.

Conjectures from Colin Barker, Jan 10 2019: (Start)

G.f.: x*(8 + 167*x + 397*x^2 + 147*x^3 + x^4) / (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:
..5....6....6....6....2....6....5....0....3....2....1....1....2....3....3....0
..4....5....5....4....1....0....0....2....4....0....6....2....6....4....3....6
..6....1....6....6....2....3....4....5....5....6....3....1....1....3....2....5
..1....6....1....2....6....0....6....0....3....4....6....5....3....1....1....4
..1....0....5....3....4....1....1....1....1....2....3....6....6....2....2....4
..0....4....6....5....2....3....6....6....0....2....6....5....2....3....1....0

Crossrefs

Row 6 of A267232.

Sequence in context: A300768 A300638 A301360 * A230144 A378804 A013377

Adjacent sequences: A267232 A267233 A267234 * A267236 A267237 A267238

Keyword

nonn

Author

R. H. Hardin, Jan 12 2016

Status

approved