

A181848


Consider two consecutive primes {p,q} such that P=2p+q and Q=2q+p are both prime. Sequence gives lesser primes p.


7



3, 5, 13, 59, 103, 113, 223, 241, 269, 337, 491, 773, 787, 823, 911, 919, 1571, 1637, 1723, 1879, 1949, 2089, 2423, 2521, 2753, 2953, 2971, 2999, 3011, 3137, 3361, 3571, 3739, 4231, 4363, 4663, 4909, 5791, 5903, 6221, 6359, 6793, 7043, 7507, 7873, 9323, 9403
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OFFSET

1,1


COMMENTS

Note that QP=qp and {P,Q} are not necessarily consecutive primes.


LINKS

Zak Seidov, Table of n, a(n) for n = 1..3000


EXAMPLE

a(1)=3 because p=3, q=5 and P=11 and Q=13 are both prime
a(3)=13 because p=13, q=17 and P=43 and Q=47 are both prime.


MATHEMATICA

a=2; Reap[Do[b=Prime[n]; If[PrimeQ[2*a+b]&&PrimeQ[2*b+a], Sow[a]]; a=b, {n, 2, 200}]][[2, 1]]


PROG

(PARI) isok(p) = isprime(p) && (q=nextprime(p+1)) && isprime(p+2*q) && isprime(q+2*p); \\ Michel Marcus, Mar 05 2016


CROSSREFS

Intersection of A173971 and A175914.  Zak Seidov, Mar 04 2016
Sequence in context: A276827 A034375 A081953 * A243161 A153207 A144718
Adjacent sequences: A181845 A181846 A181847 * A181849 A181850 A181851


KEYWORD

nonn


AUTHOR

Zak Seidov, Aug 18 2012


STATUS

approved



