A330659 The number of free polyiamonds with n cells on an order-7 triangular tiling of the hyperbolic plane.

1, 1, 1, 1, 3, 4, 12, 27, 78, 208, 637, 1870, 5797, 17866, 56237, 177573, 566904, 1818527, 5874180, 19065038

Offset: 0

Author

Peter Kagey, Mar 01 2020

Keywords

• nonn
• more

Comments

This gives the number of polyforms with n cells in the hyperbolic tiling with Schläfli symbol {3,7}.

This sequence is computed from via program by Christian Sievers in the Code Golf Stack Exchange link.

Links

• Code Golf Stack Exchange, Impress Donald Knuth by counting polyominoes on the hyperbolic plane
• Wikipedia, Order-7 triangular tiling
• Wikipedia, Polyiamond

Crossrefs

Analogs with different Schläfli symbols are A000207 ({3,oo}), A000577 ({3,6}), A005036 ({4,oo}), and A119611 ({4,5}).

Extensions

a(11)-a(19) from Ed Wynn, Feb 14 2021