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A127430 Primes p such that 6p-5 and 6p+5 are also primes. 6
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

Sequence in context: A296931 A278698 A023221 * A171595 A106483 A145673

Adjacent sequences:  A127427 A127428 A127429 * A127431 A127432 A127433

KEYWORD

nonn

AUTHOR

Zerinvary Lajos, Mar 31 2007

STATUS

approved

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Last modified September 17 18:22 EDT 2021. Contains 347489 sequences. (Running on oeis4.)