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%I #5 Oct 01 2013 21:35:21
%S 5,17,71,99,123
%N Numbers n such that the number formed by the concatenation of the consecutive integers from 5 to n is prime.
%C Primes of this form are rare. 2 and 5 are the only beginning numbers less than 100 that form more than 2 primes for all ending numbers less than 1000.
%e The 2nd entry forms the number 567891011121314151617 which is prime.
%o (PARI) consecprimes(n,m) = { local(a,x,y); a=""; for(x=m,n, a=concat(a,Str(x)); y=eval(a); if(ispseudoprime(y), print(x","y) ) ) }
%K more,nonn,base
%O 1,1
%A _Cino Hilliard_, Apr 19 2007
%E Edited by _Charles R Greathouse IV_, Apr 25 2010