OFFSET
1,1
COMMENTS
Or, position of 5 in A023509 Greatest prime divisor of n-th prime + 1.
FORMULA
A023509(m)=5.
MATHEMATICA
Reap[Do[If[FactorInteger[Prime[n]+1][[ -1, 1]]==5, Sow[n]], {n, 5000}]][[2, 1]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Sep 09 2006
STATUS
approved