From: Andy Latto <andy.latto@pobox.com>

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I can also show that the reciprocal of the smallest prime p > 10^d with primitive root 10 includes every d-digit block. I can show that if p < 2*10^d,

--you do not need this "if" because of the known theorem that there is always a prime between X and 2X if X>1: http://en.wikipedia.org/wiki/Bertrand's_postulate

Bertrand's postulate tells us there is a prime between 10^d and 2*10^d. But what I think David Wilson needs as an assumption is the stronger statement that there is a prime p between 10^d and 2*10^d such that 10 is a primitive root mod p. Andy

--Ah. Andy is right. And that is devastating because (pathetically!) it is not even known that 10 is a prim-root modulo more than a finite set of primes: http://en.wikipedia.org/wiki/Artin's_conjecture_on_primitive_roots So while I have no doubt whatever that the "10ified Bertrand conjecture" is true, a proof seems out of reach.