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 A270895 #13 Mar 29 2016 22:39:45 %S A270895 18213931681,5044241991721,6093734165401,6278567569849,17919144076201, %T A270895 52536446729209,56470430531761,72659547739249,107737943736721, %U A270895 123343213788001,136925780937841,170306127919321,211292941174561,296693149397089,321058916825689 %N A270895 Sierpiński numbers that are squares. %C A270895 This sequence contains infinitely many numbers that end in 5. See also A233469. %H A270895 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski number</a> %F A270895 A000290 INTERSECT A076336. %F A270895 a(n) = A270896(n)^2. %Y A270895 Cf. A076336, A233469, A270896. %K A270895 nonn,hard %O A270895 1,1 %A A270895 _Arkadiusz Wesolowski_, Mar 25 2016