%N Primes in A038397 (concatenate first n squares in reverse order).
%C Among the first 51 terms only three terms are prime: SmBackConSq(2), SmBackConSq(3), SmBackConSq(14), found by Micha Fleuren.
%C The next term a(4) is formed from concatenation of square of numbers from 700 to 1 and consists of 3742 digits. - _Shyam Sunder Gupta_, Jul 25 2013
%C Analogously, a(5) is probably the concatenation of squares up to 2818^2, which is a probable prime of 18269 digits, while a(6) > 10^40000. - _Giovanni Resta_, Jul 22 2013
%H M. Fleuren, <a href="http://www.gallup.unm.edu/~smarandache/SmBackConSq.txt">Smarandache Back Concatenated Squares</a>.
%Y Cf. A038397.
%A M. Grete (martha.grete(AT)web.de), Feb 21 2004