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 A385400 #6 Jun 28 2025 11:15:11 %S A385400 0,0,2,16,239,3154,42225,561178,7459089 %N A385400 a(n) is the number of free polyominoids that have faces aligned to precisely 3 planes. %H A385400 John Mason, <a href="/A385400/a385400.png">Illustration of size 4 polyominoids</a> %F A385400 a(n) = A075679(n) - A385399(n) - A000105(n). %Y A385400 Cf. A000105 (faces aligned to precisely 1 plane), A385399 (faces aligned to precisely 2 planes), A075679. %K A385400 nonn,more %O A385400 1,3 %A A385400 _John Mason_, Jun 27 2025