OFFSET
0,4
LINKS
Code Golf Stack Exchange, Impress Donald Knuth by counting polyominoes on the hyperbolic plane.
Don Hatch, Hyperbolic Planar Tesselations: {4,5}.
Greg Malen, Érika Roldán, and Rosemberg Toalá-Enríquez, Extremal {p, q}-Animals, Ann. Comb. (2023), p. 3.
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.
PROG
(GAP) # See the Code Golf Stack Exchange link.
(bc) /* See the Code Golf Stack Exchange link. */
(C) // See the Code Golf Stack Exchange link.
CROSSREFS
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
a(11)-a(14) from Ed Wynn, Feb 14 2021
STATUS
approved