OFFSET
1,1
EXAMPLE
a(1)=11 because p=3, q=5 and P=11 and Q=13 are both prime.
a(3)=43 because p=13, q=17 and P=43 and Q=47 are both prime.
MATHEMATICA
Select[Table[If[PrimeQ[2*Prime[j-1] + Prime[j]] && PrimeQ[Prime[j-1] + 2*Prime[j]], 2*Prime[j-1] + Prime[j], 0], {j, 2, 2000}], #!=0&] (* Vaclav Kotesovec, Oct 08 2014 *)
2#[[1]]+#[[2]]&/@Select[Partition[Prime[Range[1000]], 2, 1], AllTrue[ {2#[[1]]+ #[[2]], 2#[[2]]+#[[1]]}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jun 28 2017 *)
PROG
(PARI) listP(nn) = {forprime(p=2, nn, q = nextprime(p+1); if (isprime(P=2*p+q) && isprime(2*q+p), print1(P, ", ")); ); } \\ Michel Marcus, Oct 07 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Oct 07 2014
STATUS
approved