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 A270344 #22 Jun 15 2025 23:59:11
%S A270344 2,17,26,2526,5876126,8061827,8996188226,5295909711327
%N A270344 Least squarefree number that has runs of exactly n nonsquarefree numbers directly preceding and succeeding it.
%C A270344 The sequence appears to be monotone increasing, but the Mathematica implementation does not assume that.
%C A270344 Only a(0) and a(7) differ from A268330 in the numbers computed so far.
%t A270344 (* computes a(n), 1 <= n <= 5 *)
%t A270344 sfRun[n_]:=Module[{i=n}, While[SquareFreeQ[i], i++]; i-n]
%t A270344 nsfRun[n_]:=Module[{i=n}, While[!SquareFreeQ[i], i++]; i-n]
%t A270344 a270344[{low_, high_}]:=Module[{i, next, r, s, list=Table[{},5]}, For[i=low, i<=high, i+=next, r=nsfRun[i]; If[r==0, next=sfRun[i], s=nsfRun[i+r+1]; If[r==s, If[list[[r]]=={}, list[[r]]={i, i+r, i+2r}]; next=2r+2, next=r+1]]]; list]
%t A270344 Map[#[[2]]&, a270344[{0,10000000}]] (* data *)
%Y A270344 Cf. A268330.
%K A270344 nonn,more
%O A270344 0,1
%A A270344 _Hartmut F. W. Hoft_, Mar 15 2016
%E A270344 a(7) from _Giovanni Resta_, Apr 11 2016