OFFSET
1,1
COMMENTS
Terms >5 are congruent to 29 mod 30. - Zak Seidov, May 10 2012
Also 2*p1+p2 and p1+2*p2 are twin primes. - Zak Seidov, May 10 2012
LINKS
Zak Seidov, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
a(1)=3 because 3, 5 are twin primes and 2*3+5=11, 3+2*5=13 are also primes.
MAPLE
select(q -> isprime(q) and isprime(q+2) and isprime(3*q+2) and isprime(3*q+4), [3, 5, seq(i, i=29..200000, 30)]); # Robert Israel, May 06 2019
MATHEMATICA
lst={}; Do[p1=Prime[n]; p2=p1+2; If[PrimeQ[p2]&&PrimeQ[2*p1+p2]&&PrimeQ[p1+2*p2], AppendTo[lst, p1]], {n, 8!}]; lst
PROG
(Magma) [NthPrime(n): n in [1..12000] | forall{p: p in [NthPrime(n)+2, 3*NthPrime(n)+2, 3*NthPrime(n)+4] | IsPrime(p)}]; // Bruno Berselli, May 10 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Apr 02 2010
STATUS
approved