I realized that this sequence would be a(n) = smallest prime >= 10^n with primitive root 10. This made it easier to extend 1 17 2 109 3 1019 4 10007 5 100019 6 1000171 7 10000019 8 100000007 9 1000000007 -------- Original Message -------- Subject: Re: [math-fun] [EXTERNAL] Re: Fun with math: Dividing one by 998001 yields a surprising result Date: Sat, 28 Jan 2012 10:41:33 -0500 From: David Wilson <davidwwilson@comcast.net> Reply-To: math-fun <math-fun@mailman.xmission.com> To: math-fun <math-fun@mailman.xmission.com> Which made me curious... What is the smallest value a(d) such that every d-digit sequence occurs in the decimal expansion of 1/d (after the decimal point). For small d>= 1 my program says 17, 109, 1019, 10007, 100019, ... but it seems stuck on 6 digits, so perhaps there is an overflow issue. All primes slightly above 10^d, as one might expect, but not necessarily the smallest such primes. _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun