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 A155139 #18 Jul 06 2016 02:32:22
%S A155139 47,53,101,239,347,353,487,547,647,653,683,719,853,947,953,1061,1153,
%T A155139 1213,1277,1447,1453,1553,1663,1669,1693,1697,1747,1753,1847,2053,
%U A155139 2153,2251,2347,2447,2647,2659,2741,2753,2887,2953,3041,3253,3347,3359,3433
%N A155139 Primes p such that both p-+3 are not squarefree.
%C A155139 47-3=44=2^2*11, 47+3=50=2*5^2, ...
%H A155139 John Cerkan, <a href="/A155139/b155139.txt">Table of n, a(n) for n = 1..10000</a>
%t A155139 <<NumberTheory`NumberTheoryFunctions` (* needed with older versions *)
%t A155139 lst={};Do[p=Prime[n];If[ !SquareFreeQ[p-3]&&!SquareFreeQ[p+3],AppendTo[lst,p]],{n,6!}];lst
%t A155139 Select[Prime[Range[500]],!SquareFreeQ[#-3]&&!SquareFreeQ[#+3]&] (* _Harvey P. Dale_, May 01 2012 *)
%o A155139 (PARI) lista(nn) = forprime(p=3, nn, if (! issquarefree(p-3) && ! issquarefree(p+3), print1(p, ", "))); \\ _Michel Marcus_, Jul 05 2016
%Y A155139 Cf. A153213, A049282.
%K A155139 nonn
%O A155139 1,1
%A A155139 _Vladimir Joseph Stephan Orlovsky_, Jan 21 2009