OFFSET
1,1
EXAMPLE
Divisors of 6: 1,2,3,6. As 6*3*2*1 = 36, 36 - 6 - 1 = 29 is prime, and 36 + 6 + 1 = 43 is prime, 6 is a term.
MATHEMATICA
f[n_]:=PrimeQ[Times@@Divisors[n]-n-1]&&PrimeQ[Times@@Divisors[n]+n+1]; lst={}; Do[If[f[n], AppendTo[lst, n]], {n, 7!}]; lst
Select[Range[3200], AllTrue[Times@@Divisors[#]+{(#+1), (-#-1)}, PrimeQ]&] (* Harvey P. Dale, Aug 30 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Dec 14 2009
STATUS
approved