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%I #9 Jul 04 2018 08:49:13
%S 5,73,337,5449,32569,316259,3165713,31630007,316229827,3162291731,
%T 31622777629,316227771019,3162277660313,31622776613849,
%U 316227766047293,3162277660170061,31622776601693377,316227766016857441
%N Smallest n-digit prime whose square is a concatenation of two n-digit primes (no leading zeros allowed), 0 if no such prime.
%e E.g., 5449^2 = 29691601 = (2969)(1601).
%o (PARI) { a(n) = local(t,m,s); t = 10^(n-1); while(1, t=nextprime(t+1); m = nextprime(sqrtint(t*10^n)+1); s=m^2; if( s\10^n!=t, next); if( (s%10^n) > 10^(n-1) && ispseudoprime(s%10^n), return(m); ); ) } \\ _Max Alekseyev_, Apr 23 2010
%K nonn,base
%O 1,1
%A _Patrick De Geest_, Jan 15 2001
%E More terms from _Max Alekseyev_, Apr 23 2010
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