%I #14 Jun 22 2016 08:29:28
%S 1,9,121,529,841,1089,1849,3721,4489,4761,5041,5329,6561,7569,8649,
%T 9801,10609,12321,17161,23409,28561,32041,32761,33489,39601,45369,
%U 49729,51529,54289,61009,62001,63001,66049,69169,71289,76729,88209,94249
%N Squares that become prime numbers when prefixed with a 7.
%C For obvious reasons, all terms are odd. - _Harvey P. Dale_, Sep 30 2012
%C Subsequence of squares of A032670. - _Michel Marcus_, Jun 22 2016
%H G. C. Greubel, <a href="/A167722/b167722.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[1,400,2]^2,PrimeQ[FromDigits[Join[{7},IntegerDigits[#]]]]&] (* _Harvey P. Dale_, Sep 30 2012 *)
%Y Cf. A032670.
%K base,nonn
%O 1,2
%A _Claudio Meller_, Nov 10 2009