A267468 Number of length-n 0..5 arrays with no following elements larger than the first repeated value.

6, 36, 201, 1096, 5921, 31880, 171601, 925176, 5002641, 27155800, 148092161, 811801256, 4475004961, 24813260520, 138416411121, 776822970136, 4385905536881, 24907563562040, 142244725848481, 816667390335816

Offset

1,1

Comments

Column 5 of A267471.

Links

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

Formula

Empirical: a(n) = 26*a(n-1) -280*a(n-2) +1610*a(n-3) -5299*a(n-4) +9884*a(n-5) -9540*a(n-6) +3600*a(n-7).

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

G.f.: x*(6 - 120*x + 945*x^2 - 3710*x^3 + 7539*x^4 - 7336*x^5 + 2556*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)^2*(1 - 6*x)).

a(n) = (-75 - 25*2^(1+n) - 50*3^n + 25*2^(1+n)*3^n - 75*4^n + 413*5^n + 12*5^n*n) / 300.

(End)

Example

Some solutions for n=7:
..2....1....0....4....3....5....2....0....3....3....4....4....0....4....1....3
..0....3....3....1....1....0....0....4....0....3....3....3....3....4....4....1
..4....2....4....2....2....1....4....1....3....1....0....5....1....0....5....2
..0....4....1....3....0....5....0....5....0....0....3....1....2....0....2....1
..3....0....5....2....4....4....2....0....3....0....2....0....5....3....0....4
..4....2....3....2....4....1....5....4....2....3....0....1....5....2....4....3
..0....4....0....1....0....3....2....3....1....2....3....0....4....1....4....5

Crossrefs

Cf. A267471.

Sequence in context: A232138 A000551 A038157 * A225685 A006812 A111989

Adjacent sequences: A267465 A267466 A267467 * A267469 A267470 A267471

Keyword

nonn

Author

R. H. Hardin, Jan 15 2016

Status

approved