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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A160241 Number of Greek Key Tours on a 7 X n grid. 1
1, 7, 164, 1337, 16262, 144476, 1510446, 13506023, 132712481, 1185979605, 11264671456, 100572103736, 935551716239, 8347069749600, 76604373779441, 683160282998544, 6213169249692192, 55392188422262591, 500676083630457127, 4462726297606450762, 40165465812088131228, 357958181000067374304, 3212099862174948821718, 28623565473267451344466, 256312533945178149983147, 2283878397650977479239903, 20420964710002966369773032, 181952098315164452547737813, 1625193628709305194920610168, 14480051230931926406392771755 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Greek Key Tours are self-avoiding walks that touch every vertex of the grid and start at the bottom-left corner.

The sequence may be enumerated using standard methods for counting Hamilton cycles on a modified graph with two additional nodes, one joined to a corner vertex and the other joined to all other vertices. - Andrew Howroyd, Nov 07 2015

LINKS

Table of n, a(n) for n=1..30.

N. Johnston, On Maximal Self-Avoiding Walks.

CROSSREFS

Cf. A046994, A046995, A145156, A145157.

Sequence in context: A212856 A169608 A184754 * A020998 A012504 A012689

Adjacent sequences:  A160238 A160239 A160240 * A160242 A160243 A160244

KEYWORD

nonn

AUTHOR

Nathaniel Johnston, May 05 2009

EXTENSIONS

a(11)-a(30) from Andrew Howroyd, Nov 07 2015

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 October 18 18:58 EDT 2018. Contains 316323 sequences. (Running on oeis4.)