OFFSET
2,1
COMMENTS
a(n) > 2 iff A039951(n) = 2.
a(n) > 3 iff A268352(n) = 3.
Does every prime appear in the sequence?
It is easy to see that the answer to the previous question is "yes" if and only if A256236 is infinite.
The ABC-(k, Epsilon) conjecture with k >= 2 and Epsilon > 0 such that 1/(1/Epsilon + 1) + 1/k <= log(2)/(24*log(a)) implies that a(n) exists for all n (cf. Broughan, 2006; theorem 5.6).
LINKS
Felix Fröhlich, Table of n, a(n) for n = 2..10000
K. A. Broughan, Relaxations of the abc conjecture using integer k'th roots, New Zealand Journal of Mathematics, 35 (2006), 121-136.
EXAMPLE
The sequence of base-17 Wieferich primes (A128668) starts 2, 3, 46021. Thus the smallest non-Wieferich prime to base 17 is 5 and hence a(17) = 5.
PROG
(PARI) a(n) = forprime(p=1, , if(Mod(n, p^2)^(p-1)!=1, return(p)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Mar 22 2016
STATUS
approved