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 A271042 #21 Apr 20 2022 06:42:02
%S A271042 2,1,10,101,246,1685,22026,217077,7216626,8870033,262315477,221167433,
%T A271042 105779897634,82462576233
%N A271042 a(n) = k is the least squarefree number with a run of n >= 0 nonsquarefree numbers immediately preceding k and a run of zero nonsquarefree numbers immediately succeeding k.
%C A271042 This is the leftmost column (indexed by zero) of the doubly infinite matrix T(i,j) defined in A270996: a(n) = A270996(n*(n+1)/2).
%e A271042 a(3) = 101 since 97, 101 and 102 are squarefree while 98, 99 and 100 constitute the first nonsquarefree triple followed by a pair of squarefree numbers.
%t A271042 (* We use function a270996[] from A270996 *)
%t A271042 Map[a270996[{0, 1000000},{#, 0}]&,Range[0,7]]
%t A271042 (* computes a(0)...a(7) *)
%Y A271042 Cf. A005117, A268330, A270344, A270996.
%K A271042 nonn,more
%O A271042 0,1
%A A271042 _Hartmut F. W. Hoft_, Mar 29 2016
%E A271042 a(12)-a(13) from _Kevin P. Thompson_, Apr 19 2022