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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A180603 Number of "pieces" of the n-th Brillouin zone of a 2D square lattice. 2
1, 4, 8, 12, 20, 20, 12, 12, 20, 28, 44, 48, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Each Brillouin zone has the same area, and they are all equivalent mod the periodicity of the lattice, but the higher-order ones consist of a set of polygons. This is the number of polygons in that set.

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

The 2nd Brillouin zone consists of 4 right isosceles triangles, so a(2) = 4. The 4th Brillouin zone consists of 8 triangles and 4 kites, so a(4) = 12.

CROSSREFS

Sequence in context: A311648 A026042 A196377 * A311649 A311650 A311651

Adjacent sequences:  A180600 A180601 A180602 * A180604 A180605 A180606

KEYWORD

nonn,more

AUTHOR

Keenan Pepper, Sep 11 2010

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 16 12:38 EDT 2019. Contains 324152 sequences. (Running on oeis4.)