login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A221291 Equals two maps: number of 3Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..3 3Xn array 0
1, 12, 92, 673, 5912, 48298, 396846, 3240527, 26241353, 211785583, 1703772887, 13679840407, 109689414233, 878752161168, 7035829547262, 56311795445487 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 3 of A221290

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A220330 A055022 A220937 * A044263 A044644 A173348

Adjacent sequences:  A221288 A221289 A221290 * A221292 A221293 A221294

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 09 2013

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 June 23 08:44 EDT 2021. Contains 345395 sequences. (Running on oeis4.)