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A059017
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Smallest n-digit prime whose square is a concatenation of two n-digit primes (no leading zeros allowed), 0 if no such prime.
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0
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5, 73, 337, 5449, 32569, 316259, 3165713, 31630007, 316229827, 3162291731, 31622777629, 316227771019, 3162277660313, 31622776613849, 316227766047293, 3162277660170061, 31622776601693377, 316227766016857441
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| E.g. 5449^2 = 29691601 = (2969)(1601).
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PROG
| (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); ); ) } [From Max Alekseyev (maxale(AT)gmail.com), Apr 23 2010]
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CROSSREFS
| Sequence in context: A206280 A070526 A070530 * A099667 A108444 A155662
Adjacent sequences: A059014 A059015 A059016 * A059018 A059019 A059020
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KEYWORD
| nonn,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Jan 15 2001.
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EXTENSIONS
| More terms from Max Alekseyev (maxale(AT)gmail.com), Apr 23 2010
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