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 A118728 #18 Dec 10 2024 08:58:48
%S A118728 0,1,2,3,5,10,15,26,41,67,109,177,286,463,749,1213,1963,3178,5141,
%T A118728 8319,13461,21781,35242,57023,92265,149289,241554,390845,632399,
%U A118728 1023245,1655645,2678890,4334537,7013427,11347966,18361393,29709359
%N A118728 a(n) = smallest squarefree number not less than a(n-1)+a(n-2), a(1)=1, a(0)=0.
%H A118728 Vincenzo Librandi, <a href="/A118728/b118728.txt">Table of n, a(n) for n = 0..200</a>
%F A118728 a(n) = A067535*(a(n-2)+a(n-1)) for n>1.
%t A118728 Module[{lst={0,1}},Do[Module[{k=Total[Take[lst,-2]]}, While[!SquareFreeQ[ k], k++];AppendTo[lst,k]],{40}];Join[{0},Drop[lst,2]]] (* _Harvey P. Dale_, May 16 2012 *)
%t A118728 ssn[{a_,b_}]:=Module[{k=a+b},While[!SquareFreeQ[k],k++];k]; Join[{0},Drop[NestList[ {#[[2]],ssn[#]}&,{0,1},40][[;;,1]],2]] (* _Harvey P. Dale_, Aug 12 2024 *)
%Y A118728 Cf. A000045, A005117.
%K A118728 nonn
%O A118728 0,3
%A A118728 _Reinhard Zumkeller_, May 21 2006