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 A173086 #6 Sep 06 2025 15:48:50
%S A173086 4,10,49,95,121,217,247,289,295,301,305,335,371,427,469,493,535,551,
%T A173086 581,583,707,721,745,749,767,815,817,835,851,893,899,901,973,1099,
%U A173086 1169,1205,1219,1253,1333,1349,1379,1405,1501,1603,1685,1711,1739,1751,1757,1765
%N A173086 Numbers k such that k, k^2 - 6, and k^2 + 6 are semiprime.
%e A173086 4=2*2, 4^2-6=10=2*5, 4^2+6=22=2*11, so 4 is in the sequence.
%t A173086 f[n_]:=Last/@FactorInteger[n]=={1,1}||Last/@FactorInteger[n]=={2}; lst={};Do[If[f[n], a=n^2-6;b=n^2+6;If[f[a]&&f[b],AppendTo[lst,n]]],{n,8!}];lst
%Y A173086 Cf. A001358, A173082, A173083, A173084, A173085
%K A173086 nonn,changed
%O A173086 1,1
%A A173086 _Vladimir Joseph Stephan Orlovsky_, Feb 09 2010
%E A173086 Edited by _Charles R Greathouse IV_, Apr 06 2010