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 A167717 #11 May 21 2023 11:46:54
%S A167717 9,81,441,729,1089,1521,6561,8649,16641,19881,33489,53361,56169,71289,
%T A167717 74529,84681,88209,103041,168921,173889,251001,257049,263169,269361,
%U A167717 288369,301401,314721,335241,370881,423801,463761,514089,549081,558009
%N A167717 Squares that become a prime number when prefixed with a 2.
%C A167717 Subsequence of squares of A032665. - _Michel Marcus_, Jun 21 2016
%H A167717 G. C. Greubel, <a href="/A167717/b167717.txt">Table of n, a(n) for n = 1..10000</a>
%t A167717 Select[Range[1, 500, 2]^2, PrimeQ[FromDigits[Join[{2}, IntegerDigits[#]]]] &](* _G. C. Greubel_, Jun 21 2016 *)
%t A167717 Select[Range[800]^2,PrimeQ[2*10^IntegerLength[#]+#]&] (* _Harvey P. Dale_, Oct 23 2022 *)
%Y A167717 Cf. A032665.
%K A167717 base,nonn
%O A167717 1,1
%A A167717 _Claudio Meller_, Nov 10 2009