A267469 Number of length-n 0..6 arrays with no following elements larger than the first repeated value.

7, 49, 322, 2072, 13216, 83972, 532840, 3381860, 21491464, 136856180, 873803848, 5596638788, 35973158152, 232118471828, 1503949949896, 9786663686756, 63969334316680, 420026972347316, 2770499256109384, 18356852895660164

Offset

1,1

Comments

Column 6 of A267471.

Links

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

Formula

Empirical: a(n) = 34*a(n-1) -490*a(n-2) +3892*a(n-3) -18529*a(n-4) +53746*a(n-5) -91860*a(n-6) +83448*a(n-7) -30240*a(n-8).

Conjectures from Colin Barker, Feb 05 2018: (Start)

G.f.: x*(7 - 189*x + 2086*x^2 - 12110*x^3 + 39543*x^4 - 71617*x^5 + 65212*x^6 - 22212*x^7) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)^2*(1 - 7*x)).

a(n) = (-504 - 315*2^n - 280*3^n - 315*4^n - 504*5^n + 3409*6^n + 360*7^n + 35*2^(1+n)*3^n*n) / 2520.

(End)

Example

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

Crossrefs

Cf. A267471.

Sequence in context: A200783 A267230 A188868 * A126639 A268942 A269638

Adjacent sequences: A267466 A267467 A267468 * A267470 A267471 A267472

Keyword

nonn

Author

R. H. Hardin, Jan 15 2016

Status

approved