This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A330659 #32 Feb 15 2021 01:56:42
%S A330659 1,1,1,1,3,4,12,27,78,208,637,1870,5797,17866,56237,177573,566904,
%T A330659 1818527,5874180,19065038
%N A330659 The number of free polyiamonds with n cells on an order-7 triangular tiling of the hyperbolic plane.
%C A330659 This gives the number of polyforms with n cells in the hyperbolic tiling with Schläfli symbol {3,7}.
%C A330659 This sequence is computed from via program by _Christian Sievers_ in the Code Golf Stack Exchange link.
%H A330659 Code Golf Stack Exchange, <a href="https://codegolf.stackexchange.com/a/200295/53884">Impress Donald Knuth by counting polyominoes on the hyperbolic plane</a>
%H A330659 Wikipedia, <a href="https://en.wikipedia.org/wiki/Order-7_triangular_tiling">Order-7 triangular tiling</a>
%H A330659 Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyiamond">Polyiamond</a>
%o A330659 Several working programs are available via the Code Golf link.
%Y A330659 Analogs with different Schläfli symbols are A000207 ({3,oo}), A000577 ({3,6}), A005036 ({4,oo}), and A119611 ({4,5}).
%K A330659 nonn,more
%O A330659 0,5
%A A330659 _Peter Kagey_, Mar 01 2020
%E A330659 a(11)-a(19) from _Ed Wynn_, Feb 14 2021