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 A055554 #11 Mar 16 2017 11:26:05 %S A055554 242,1757711582,3515422922,5273134262,7030845602,8788556942, %T A055554 10546268282,12303979622,14061690962,15819402302,17577113642, %U A055554 19334824982,21092536322,22850247662,24607959002,26365670342 %N A055554 An arithmetic progression each term of which is followed by at least 4 nonsquarefree consecutive integers. %C A055554 From the terms of A051681 or A045882 similar progressions for longer chains can be constructed. %H A055554 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A055554 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2, -1). %F A055554 a(n) = d*n + 242, where d = LCM(242, 243, 244, 245) = 1757711340 = 2*2*3*3*3*3*3*5*7*11*11*61. %Y A055554 Cf. A005117, A013929, A053806, A053797, A045882, A051681. %K A055554 nonn %O A055554 1,1 %A A055554 _Labos Elemer_, Jul 10 2000