Primes p such that the decimal fraction 1/p has same period length as 1/p^2.
No further terms below 3.4*10^13 (cf. Fischer's table)
REFERENCES
J. Brillhart, J. Tonascia, and P. Weinberger, On the Fermat quotient, pp. 213-222 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
Richard K. Guy, Unsolved Problems in Number Theory, Springer, 2004, A3.
Peter L. Montgomery, New Solutions of a^(p-1) = 1 (mod p^2), Math. Comp. 61 (1993), 361-363.
Samuel Yates, The Mystique of Repunits, Math. Mag. 51 (1978), 22-28.
