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 A283110 #16 Feb 26 2023 08:42:46 %S A283110 0,1,4,13,44,153,544,1965,7185,26536,98822,370593,1398029,5300984, %T A283110 20189792,77198271,296202907,1140024698,4399918134,17024040984, %U A283110 66018733123,256549059895,998839762846,3895616434744,15217813245743,59534874351097,233231355731136,914864639728729 %N A283110 Increase in the number of fixed polyominoes from order n to order n+1. %H A283110 John Mason, <a href="/A283110/b283110.txt">Table of n, a(n) for n = 0..55</a> %F A283110 a(n) = A001168(n+1) - A001168(n); this holds for n=0 if A001168(0) is set conventionally to 1, like it is done for free polyominoes in A000105. We say there are exactly 1 fixed polyominoes of order 0. %Y A283110 Cf. A001168. %K A283110 nonn %O A283110 0,3 %A A283110 _Francois Alcover_, Feb 28 2017