A127430 - OEIS

A127430

Primes p such that 6p-5 and 6p+5 are also primes.

2, 3, 7, 11, 13, 17, 31, 41, 59, 71, 73, 97, 113, 139, 157, 193, 239, 269, 277, 311, 337, 349, 421, 449, 487, 577, 587, 619, 643, 701, 811, 823, 827, 941, 977, 1021, 1051, 1093, 1217, 1249, 1259, 1361, 1373, 1471, 1571, 1721, 1723, 1747, 1777, 1789, 1861, 1907

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Subsequence of primes p such that 6p-5 and 6p+5 are consecutive primes: 31, 41, 71, 97, 139, 193, 337, 349, 421, 487, 587, 619, 643, 701, 811, 827, 1021, 1051, 1093, 1217, 1249, 1259, 1471, 1571, 1721, 1747, .... - Zak Seidov, Mar 27 2017

LINKS

Table of n, a(n) for n=1..52.

EXAMPLE

Example: 11, 6*11+5=71, 6*11-5=61 are all primes.

MAPLE

A127430:=n->`if`(isprime(n) and isprime(6*n-5) and isprime(6*n+5), n, NULL): seq(A127430(n), n=1..2000); # Wesley Ivan Hurt, Oct 23 2014

MATHEMATICA

Select[Range[5000], PrimeQ[ # ] && PrimeQ[6# + 5] && PrimeQ[6# - 5] &]

PROG

(Magma) [ p: p in PrimesUpTo(9000) | IsPrime(6*p-5) and IsPrime(6*p+5)] // - Vincenzo Librandi, Jan 29 2011

(PARI) is(n)=isprime(n) && isprime(6*n-5) && isprime(6*n+5) \\ Charles R Greathouse IV, Mar 28 2017

CROSSREFS