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!)
A190417 Number of (n+2)X(n+2) symmetric binary matrices without the pattern 1 1 1 vertically or horizontally 1
45, 497, 9580, 319760, 18980021, 1980733945, 363632891784, 117655174702396, 67024501865532719, 67232893079939036305, 118774251891797912665388, 369496334618903888548799176, 2024200318811320542229843621759 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..18

EXAMPLE

Some solutions for n=2

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

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

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

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

CROSSREFS

Sequence in context: A086576 A295319 A147808 * A093529 A197501 A283116

Adjacent sequences: A190414 A190415 A190416 * A190418 A190419 A190420

KEYWORD

nonn

AUTHOR

R. H. Hardin May 10 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 21:00 EST 2022. Contains 358648 sequences. (Running on oeis4.)