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 A227897 #21 Feb 09 2021 02:39:38
%S A227897 4,5,13,14,19,22,23,24,31,32,40,41,49,50,58,59,63,67,68,71,76,77,85,
%T A227897 86,94,95,102,103,104,112,113,121,122,130,131,139,140,148,149,157,158,
%U A227897 166,167,175,176,184,185,193,194,202,203,211,212,218,220,221,223,229
%N A227897 Numbers k such that k^2 + 2 is not squarefree.
%C A227897 Primes dividing k^2 + 2 at least twice are in A033200. - _Charles R Greathouse IV_, Oct 14 2013
%H A227897 Amiram Eldar, <a href="/A227897/b227897.txt">Table of n, a(n) for n = 1..10000</a>
%F A227897 {k: k^2 + 2 is in A013929}.
%e A227897 4 is in the sequence because 4^2 + 2 = 18 = 2 * 3^2, which is not squarefree.
%e A227897 5 is in the sequence because 5^2 + 2 = 27 = 3^3, which is not squarefree.
%e A227897 6 is not in the sequence because 6^2 + 2 = 38 = 2 * 19, which is squarefree.
%t A227897 Select[Range[300], ! SquareFreeQ[#^2 + 2] &] (* _T. D. Noe_, Oct 14 2013 *)
%t A227897 (* The following works in Mathematica versions prior to 6.0 *) Select[Range[250], MoebiusMu[#^2 + 2] == 0 &] (* _Alonso del Arte_, Oct 14 2013 *)
%o A227897 (PARI) is(n)=!issquarefree(n^2+2) \\ _Charles R Greathouse IV_, Oct 14 2013
%Y A227897 Cf. A033200, A013929, A228140.
%K A227897 nonn,easy
%O A227897 1,1
%A A227897 _Gerasimov Sergey_, Oct 14 2013