OFFSET
1,1
COMMENTS
Or, primes p such that p+2 and 2 + 4*p + p^2 are prime.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
3, 5 and 3*5+3+5=23 are prime; 5, 7 and 5*7+5+7=47 are prime; 11, 13 and 11*13+11+13 are primes.
MATHEMATICA
lst={}; Do[p=Prime[n]; r=p+2; If[PrimeQ[r], If[PrimeQ[p*r+p+r], AppendTo[lst, p]]], {n, 8!}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 28 2009 *)
Transpose[Select[Select[Partition[Prime[Range[1500]], 2, 1], #[[2]]- #[[1]] == 2&], PrimeQ[Times@@#+Total[#]]&]][[1]] (* Harvey P. Dale, Aug 24 2014 *)
PROG
(PARI) is(n)=isprime(n)&&isprime(n+2)&&isprime(n^2+4*n+2) \\ Charles R Greathouse IV, Jan 29 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Mar 10 2007
STATUS
approved