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

0,5

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

Table of n, a(n) for n=0..19.

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

Wikipedia, Order-7 triangular tiling

Wikipedia, Polyiamond

Prog

Several working programs are available via the Code Golf link.

Crossrefs

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

Sequence in context: A000942 A255436 A197459 * A000207 A002986 A147569

Adjacent sequences: A330656 A330657 A330658 * A330660 A330661 A330662

Keyword

nonn,more

Author

Peter Kagey, Mar 01 2020

Extensions

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

Status

approved