login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A198717 Number of n X 2 0..6 arrays with values 0..6 introduced in row major order and no element equal to any horizontal or vertical neighbor. 3
1, 4, 34, 499, 10507, 272410, 7817980, 234638905, 7176366133, 221220625936, 6841771033846, 211886983790431, 6565800345745279, 203504808219690982, 6308194354577750032, 195548116214389189477, 6061914804816147034345 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A198723.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 55*a(n-1) - 918*a(n-2) + 5818*a(n-3) - 13417*a(n-4) + 8463*a(n-5).

Conjectures from Colin Barker, Feb 22 2018: (Start)

G.f.: x*(1 - 51*x + 732*x^2 - 3517*x^3 + 4419*x^4) / ((1 - x)*(1 - 3*x)*(1 - 7*x)*(1 - 13*x)*(1 - 31*x)).

a(n) = 11/30 + 3^n/8 + 7^(n-1)/6 + 13^(n-1)/12 + 31^(n-1)/120.

(End)

EXAMPLE

Some solutions with all values 0 to 6 for n=4:

..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1

..2..3....2..3....2..3....2..3....2..3....2..3....2..0....2..3....2..3....2..3

..4..5....4..5....4..5....4..5....4..1....4..5....3..4....4..5....4..0....1..4

..6..1....6..0....2..6....6..2....5..6....6..4....5..6....0..6....5..6....5..6

CROSSREFS

Cf. A198723.

Sequence in context: A111169 A274244 A002105 * A198908 A207864 A222077

Adjacent sequences:  A198714 A198715 A198716 * A198718 A198719 A198720

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 29 2011

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified May 24 09:32 EDT 2018. Contains 304517 sequences. (Running on oeis4.)