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A091314 Primes in A038397 (concatenate first n squares in reverse order). 12


%S 41,941,196169144121100816449362516941

%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.

%K nonn,bref,base,less

%O 1,1

%A M. Grete (martha.grete(AT)web.de), Feb 21 2004

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Last modified April 15 08:18 EDT 2021. Contains 342977 sequences. (Running on oeis4.)