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

Offset: 1

Author

Zerinvary Lajos, Mar 31 2007

Keywords

• nonn

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

Examples

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

Programs

Magma

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

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] &]

PARI

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