OFFSET
1,1
COMMENTS
EXAMPLE
15 is a member because p(15)=47, q=(p-1)/2=23, r=(q-1)2=11 and s=(r-1)=5 are primes.
MATHEMATICA
se3=Select[(Select[(Select[(Prime[Range[30000]]-1)/2, PrimeQ]-1)/2, PrimeQ]-1)/2, PrimeQ]; Map[PrimePi, Map[2(2(2*#+1)+1)+1&, se3]]
tspQ[n_]:=And@@PrimeQ[NestList[(#-1)/2&, Prime[n], 3]]; Select[ Range[ 100000], tspQ] (* Harvey P. Dale, Jul 17 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Sep 04 2002
EXTENSIONS
More terms from Harvey P. Dale, Jul 17 2011
STATUS
approved