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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A181219 Number of nX3 binary matrices with no three 1's adjacent in a line horizontally, vertically, diagonally or antidiagonally 1
7, 49, 230, 1209, 6475, 34020, 179097, 944514, 4978956, 26241679, 138316703, 729070278, 3842881010, 20255521442, 106765644778, 562755120940, 2966245831625, 15634892911279, 82410528967137, 434380653636920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A181224

LINKS

R. H. Hardin, Table of n, a(n) for n=1..350

FORMULA

Empirical: a(n)=2*a(n-1)+8*a(n-2)+38*a(n-3)+51*a(n-4)+41*a(n-5)-48*a(n-6)-88*a(n-7)-4*a(n-8)-8*a(n-9)-15*a(n-10)+14*a(n-11)-7*a(n-12)+a(n-13)-2*a(n-14)

EXAMPLE

Some avoided solutions for 4X3

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

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

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

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

CROSSREFS

Sequence in context: A188517 A206878 A206780 * A141783 A181479 A223842

Adjacent sequences:  A181216 A181217 A181218 * A181220 A181221 A181222

KEYWORD

nonn

AUTHOR

R. H. Hardin Oct 10 2010

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified December 21 09:07 EST 2014. Contains 252300 sequences.