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%I #2 Mar 30 2012 17:33:49
%S 3,35,3517,3517257,351725765537
%N Concatenation of first n Fermat primes.
%Y Cf. A000215, A007908, A019518. Fermat primes: A019434.
%K easy,nonn,base
%O 1,1
%A _Omar E. Pol_, Oct 16 2007