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 A121150 #9 Feb 16 2025 08:33:02 %S A121150 4,6,8,9,11,12,14,15,16,18,19,20,22,23,24,25,27,28 %N A121150 Minimal number of vertices in an n-polyomino. %C A121150 It appears that a(n) = A080037[n] = n + Floor[Sqrt[4n-3]] + 2 for n>0. %H A121150 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Polyomino.html">Polyomino</a>. %Y A121150 Cf. A080037. %K A121150 nonn,more %O A121150 1,1 %A A121150 _Alexander Adamchuk_, Aug 12 2006 %E A121150 a(17)-a(18) from _John Mason_, Aug 14 2021