A267234 Number of length-5 0..n arrays with no following elements greater than or equal to the first repeated value.

7, 103, 564, 1980, 5375, 12327, 25088, 46704, 81135, 133375, 209572, 317148, 464919, 663215, 924000, 1260992, 1689783, 2227959, 2895220, 3713500, 4707087, 5902743, 7329824, 9020400, 11009375, 13334607, 16037028, 19160764, 22753255, 26865375

Offset

1,1

Links

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

Formula

Empirical: a(n) = n^5 + (37/12)*n^4 + (5/2)*n^3 + (5/12)*n^2.

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

G.f.: x*(7 + 61*x + 51*x^2 + x^3) / (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:
..3....6....4....4....0....0....4....6....5....5....5....0....2....0....4....0
..2....6....2....1....4....5....1....0....4....0....1....3....5....1....1....2
..1....2....3....6....3....1....6....3....0....1....4....6....6....6....0....1
..6....1....6....6....6....3....3....4....4....0....5....3....4....5....1....3
..0....4....6....5....5....1....4....6....5....5....6....5....4....4....1....4

Crossrefs

Row 5 of A267232.

Sequence in context: A140633 A142400 A032460 * A246914 A274670 A188946

Adjacent sequences: A267231 A267232 A267233 * A267235 A267236 A267237

Keyword

nonn

Author

R. H. Hardin, Jan 12 2016

Status

approved