OFFSET
1,1
COMMENTS
The corresponding n are 2, 8, 14, ...
EXAMPLE
7 is a term because A124271(2) = 7 is prime.
MATHEMATICA
Do[f=Sum[(Prime[i]^n-1)/(Prime[i]-1), {i, 1, n}]; If[PrimeQ[f], Print[{n, f}]], {n, 1, 100}]
CROSSREFS
KEYWORD
bref,hard,more,nonn
AUTHOR
Alexander Adamchuk, Oct 23 2006
STATUS
approved