login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A206728 Number of n X 2 0..2 arrays avoiding the pattern z-1 z-1 z in any row, column or nw-to-se diagonal. 4
9, 81, 625, 4761, 36100, 273529, 2073600, 15721225, 119202724, 903844096, 6853356225, 51965305681, 394024865796, 2987677680100, 22653944467456, 171772609502025, 1302458795084836, 9875840600125696, 74883157850128384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A206734.

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) -6*a(n-2) -43*a(n-3) +34*a(n-4) +162*a(n-5) -133*a(n-6) -13*a(n-7) +62*a(n-8) -14*a(n-9) -15*a(n-10) -6*a(n-11) +8*a(n-12) -a(n-13) -2*a(n-14) +a(n-15).

a(n) = A206727(n)^2. - Mark van Hoeij, May 14 2013

EXAMPLE

Some solutions for n=4:

..0..2....1..2....2..0....0..2....2..1....2..0....2..0....1..2....0..1....0..2

..0..1....2..0....1..2....1..1....2..1....0..2....1..2....2..2....2..1....0..2

..2..0....0..1....0..2....2..0....2..0....1..0....0..2....1..2....2..0....2..2

..1..0....1..2....1..0....0..1....1..2....1..2....2..0....2..2....0..0....0..2

CROSSREFS

Sequence in context: A213297 A272243 A272242 * A206857 A073531 A206694

Adjacent sequences: A206725 A206726 A206727 * A206729 A206730 A206731

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 11 2012

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 8 07:38 EST 2022. Contains 358691 sequences. (Running on oeis4.)