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 A365559 #17 Mar 09 2025 13:04:07 %S A365559 1,2,7,28,160,1085,8403,69824,607988,5448444,49846437,462977928 %N A365559 Number of free n-polysticks (or polyedges) in 3 dimensions. %C A365559 a(1)-a(8) verified and a(9)-a(10) computed by _John Mason_. %H A365559 Ishino Keiichiro, <a href="https://puzzlewillbeplayed.com/Polyedges/">Polyedge</a>, Puzzle will be played, 2009. %H A365559 <a href="/index/Pol#polyominoes">Index entries for sequences related to polyominoes</a>. %e A365559 There are a(3) = 7 free 3-polysticks in 3 dimensions: A019988(3) = 5 properly 1- or 2-dimensional (straight, "U", "T", "L", and skew, similar to the 5 tetrominoes) and 2 properly 3-dimensional (one path-like and one with a vertex of degree 3). %Y A365559 Sum of first three columns of A365566. %Y A365559 Cf. A019988 (2 dimensions), A365560 (fixed), A365561 (4 dimensions), A365563 (5 dimensions), A365565 (arbitrary dimension). %Y A365559 14th row of A366766. %K A365559 nonn,hard,more %O A365559 1,2 %A A365559 _Pontus von Brömssen_, Sep 09 2023 %E A365559 a(11) derived from Ishino Keiichiro's website (sum of 2-sided 2D-edges and 3D-edges), added by _Pontus von Brömssen_, Dec 21 2023 %E A365559 a(12) from _John Mason_, Mar 07 2025