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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A075212 Number of polyhexes with n cells that tile the plane by translation or by 180-degree rotation (Conway criterion). 10
1, 1, 3, 7, 21, 75, 257, 930, 3104, 9265, 21304, 81392, 139612, 427454, 1176912, 2491134, 4319362, 16243200, 21965930, 76738851, 158374741 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

Branko Gr├╝nbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Section 9.4.

LINKS

Table of n, a(n) for n=1..21.

Joseph Myers, Polyhex tiling

CROSSREFS

Cf. A070766, A075207, A075208, A075209, A075210, A075211, A075213, A075214, A075215, A075203, A075221.

Sequence in context: A001576 A169587 A075211 * A173794 A049365 A288849

Adjacent sequences:  A075209 A075210 A075211 * A075213 A075214 A075215

KEYWORD

hard,nonn

AUTHOR

Joseph Myers, Sep 08 2002

EXTENSIONS

More terms from Joseph Myers, Nov 08 2003

a(20) and a(21) from Joseph Myers, Nov 21 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 18 09:17 EST 2017. Contains 294879 sequences.