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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A019988 Number of ways of embedding a connected graph with n edges in the square lattice. 4
1, 2, 5, 16, 55, 222, 950, 4265, 19591, 91678, 434005, 2073783, 9979772, 48315186, 235088794, 1148891118, 5636168859 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

Ed Pegg, Jr., Illustrations of polyforms

M. Keller, Counting polyforms

Eric Weisstein's World of Mathematics, Polyedge [From Eric W. Weisstein, Apr 24 2009]

CROSSREFS

Sequence in context: A149972 A026106 A066642 * A137732 A057973 A102461

Adjacent sequences:  A019985 A019986 A019987 * A019989 A019990 A019991

KEYWORD

nonn,nice,hard,more

AUTHOR

Russ Cox

EXTENSIONS

More terms from Brendan Owen (brendan_owen(AT)yahoo.com), Feb 20 2002

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified November 28 22:29 EST 2014. Contains 250437 sequences.