OFFSET
1,1
COMMENTS
Equivalently, smallest prime of the form (p^(k+1)-1)/(p-1), where p is the n-th prime.
For p prime, the sum of divisors of p^k is Sum_{j=0..k} p^j, so a(n) is the smallest prime of the form sigma(prime(n)^k) where sigma is the sum of divisors function A000203.
For the corresponding values of k, see A279069.
a(15) = 1 + 47 + 47^2 + ... + 47^126 = 4.93935...*10^210.
a(57) > 10^10000.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon E. Schoenfield, Dec 22 2016; edited Dec 23 2016
STATUS
approved