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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A183730 1/16 the number of (n+1) X 2 0..7 arrays with every 2 X 2 subblock strictly increasing clockwise or counterclockwise with one decrease, and at least two adjacent blocks having the same increasing direction. 1
0, 21, 563, 9403, 135578, 1814815, 23204876, 287769879, 3491293862, 41667398364, 490998416023, 5727556631915, 66266101711488, 761498455531330, 8701271226331052, 98948856313647335, 1120614615517688964 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A183738.

LINKS

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

FORMULA

Empirical: a(n)=18*a(n-1)-46*a(n-2)-342*a(n-3)-33*a(n-4)+435*a(n-5)-157*a(n-6)-37*a(n-7)+21*a(n-8)-2*a(n-9).

EXAMPLE

Some solutions with the first block increasing clockwise for 3 X 2:

..4..5....6..0....1..2....1..2....2..4....4..5....7..0....2..3....0..2....0..2

..2..6....5..1....7..4....0..3....0..5....1..6....6..1....1..4....7..3....6..3

..1..7....4..2....6..5....7..4....7..6....0..7....4..3....0..7....6..4....5..4

...

...R.......R.......R.......R.......R.......R.......R.......R.......R.......R...

...R.......R.......R.......R.......R.......R.......R.......R.......R.......R...

CROSSREFS

Sequence in context: A297635 A292062 A194022 * A199254 A199199 A089457

Adjacent sequences:  A183727 A183728 A183729 * A183731 A183732 A183733

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 06 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 19:59 EDT 2019. Contains 327282 sequences. (Running on oeis4.)