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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A119611 Number of free polyominoes in {4,5} tessellation of the hyperbolic plane. 5
1, 1, 1, 2, 5, 16, 55, 224, 978, 4507, 21430 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..10.

Code Golf Stack Exchange Impress Donald Knuth by counting polyominoes on the hyperbolic plane

Don Hatch, Hyperbolic Planar Tesselations: {4,5}.

Peter Kagey, Example of the a(5)=16 free pentominoes in {4,5} tessellation of the hyperbolic plane.

Eric Weisstein's World of Mathematics, Polyomino.

Wikipedia, Order-5 square tiling

EXAMPLE

For n = 0,1,2,3 the polyominoes in the {4,5} tessellation of the hyperbolic plane are essentially same as the ordinary polyominoes in the plane (A000105), with redefinition of "straight line" and angular deficiency at a vertex.

For n = 4, the square tetromino does not exist. In its place is the cut-square, a pentagonal pentomino with one cell removed.

For n = 5, see links section.

CROSSREFS

Cf. A000105.

Sequence in context: A333233 A019988 A137732 * A057973 A102461 A176332

Adjacent sequences:  A119608 A119609 A119610 * A119612 A119613 A119614

KEYWORD

nonn,more

AUTHOR

Jonathan Vos Post, Jun 04 2006

EXTENSIONS

a(5) corrected by Don Knuth

a(6) corrected by Christian Sievers

a(7)-a(10) from Christian Sievers

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 November 30 05:31 EST 2020. Contains 338781 sequences. (Running on oeis4.)