OFFSET
1,1
COMMENTS
(47-1)/2=23,(23-1)/2=11,(11-1)/2=5,(5-1)/2=2(prime),...
MATHEMATICA
lst={}; Do[p=Prime[n]; If[PrimeQ[a=(p-1)/2]&&PrimeQ[b=(a-1)/2]&&PrimeQ[c=(b-1)/2]&&PrimeQ[(c-1)/2], AppendTo[lst, p]], {n, 10!}]; lst
Select[Prime[Range[711000]], AllTrue[Rest[NestList[(#-1)/2&, #, 4]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 31 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Feb 27 2009
STATUS
approved