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 A228140 #38 Jun 14 2021 13:59:54
%S A228140 10,39,45,58,59,88,108,116,137,156,157,186,206,235,244,255,284,304,
%T A228140 333,334,338,353,373,382,402,414,431,451,477,480,500,529,533,549,578,
%U A228140 598,623,627,647,665,676,685,696,717,725,745,774,794,822,823,843,845,872,892,902,912,921,941
%N A228140 Numbers n such that n^2 - 2 is not squarefree.
%H A228140 Robert Israel, <a href="/A228140/b228140.txt">Table of n, a(n) for n = 1..10000</a>
%F A228140 {n: A008865(n) in A013929} . - _R. J. Mathar_, Sep 26 2013
%p A228140 remove(n -> numtheory:-issqrfree(n^2-2), [$1..1000]); # _Robert Israel_, Nov 03 2019
%t A228140 Select[Range[1000],!SquareFreeQ[#^2-2]&] (* _Harvey P. Dale_, Jun 14 2021 *)
%Y A228140 Cf. A005117, A008865, A013929, A173186.
%K A228140 nonn
%O A228140 1,1
%A A228140 _Gerasimov Sergey_, Aug 12 2013
%E A228140 Corrected by _R. J. Mathar_, Sep 26 2013