A267236 Number of length-7 0..n arrays with no following elements greater than or equal to the first repeated value.

9, 479, 5646, 34396, 143695, 469623, 1291052, 3121008, 6830757, 13811655, 26179802, 47028540, 80733835, 133317583, 212873880, 330063296, 498680193, 736298127, 1064998374, 1512186620, 2111502855, 2903829511, 3938402884

Offset

1,1

Links

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

Formula

Empirical: a(n) = n^7 + (69/20)*n^6 + (7/2)*n^5 + (7/6)*n^4 - (7/60)*n^2.

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

G.f.: x*(9 + 407*x + 2066*x^2 + 2136*x^3 + 421*x^4 + x^5) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

Example

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

Crossrefs

Row 7 of A267232.

Sequence in context: A213447 A128947 A293951 * A357768 A306820 A157595

Adjacent sequences: A267233 A267234 A267235 * A267237 A267238 A267239

Keyword

nonn

Author

R. H. Hardin, Jan 12 2016

Status

approved