OFFSET
1,1
COMMENTS
It is believed that this is a supersequence of A001220 (Wieferich primes).
LINKS
Arkadiusz Wesolowski, Table of n, a(n) for n = 1..1000
John Blythe Dobson, A note on the two known Wieferich Primes
Wells Johnson, On the nonvanishing of Fermat quotients (mod p), Journal f. die reine und angewandte Mathematik 292, (1977): 196-200.
Wikipedia, Repdigit
EXAMPLE
103 is in the sequence because it is prime and 102 = 66 (base 16).
463 is in the sequence because it is prime and 462 = ee (base 32).
7 is not in the sequence since 6 = 6 (base 8) and 8 > 7.
MATHEMATICA
lst = {}; r = 13; Do[If[PrimeQ[p] && Length@Union@IntegerDigits[p - 1, 2^b] == 1, AppendTo[lst, p]], {b, 2, r - 1}, {p, 2^b + 1, 2^r - 1, 2}]; Union[lst]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Arkadiusz Wesolowski, Jun 10 2013
STATUS
approved