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 A385399 #7 Jun 28 2025 11:15:06 %S A385399 0,1,5,33,197,1461,11278,93486,799261 %N A385399 a(n) is the number of free polyominoids that have faces aligned to precisely 2 planes. %H A385399 John Mason, <a href="/A385399/a385399.png">Illustration of size 3 polyominoids</a> %F A385399 a(n) = A075679(n) - A385400(n) - A000105(n). %Y A385399 Cf. A000105 (faces aligned to precisely 1 plane), A385400 (faces aligned to precisely 3 planes), A075679. %K A385399 nonn,more %O A385399 1,3 %A A385399 _John Mason_, Jun 27 2025