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 A343398 #36 Jun 06 2025 03:29:12 %S A343398 1,2,1,4,9,30,97,373,1405,5630,22672,93045,384403,1602156,6712128, %T A343398 28268504,119537113,507375130,2160476897,9226446455,39504435891 %N A343398 Number of generalized polyforms on the trihexagonal tiling with n cells. %C A343398 This sequence counts "free" polyforms where holes are allowed. This means that two polyforms are considered the same if one is a rigid transformation (translation, rotation, reflection or glide reflection) of the other. %H A343398 Peter Kagey, <a href="/A343398/a343398.hs.txt">Haskell program for computing sequence</a>. %H A343398 Peter Kagey, <a href="/A343398/a343398.pdf">The a(4) = 9 generalized polyforms on the trihexagonal tiling with 4 cells</a>. %H A343398 Wikipedia, <a href="https://en.wikipedia.org/wiki/Trihexagonal_tiling">Trihexagonal tiling</a> %Y A343398 Same but distinguishing mirror images: A350739. %Y A343398 Analogous for other tilings: A000105 (square), A000228 (hexagonal), A000577 (triangular), A197156 (prismatic pentagonal), A197159 (floret pentagonal), A197459 (rhombille), A197462 (kisrhombille), A197465 (tetrakis square), A309159 (snub square), A343406 (truncated hexagonal), A343577 (truncated square). %K A343398 nonn,more,hard %O A343398 0,2 %A A343398 _Peter Kagey_, Apr 13 2021 %E A343398 a(12)-a(15) from _John Mason_, Mar 04 2022 %E A343398 a(16)-a(20) from _Bert Dobbelaere_, Jun 06 2025