

A103802


Primes p such that 2p  9 and 2p + 9 are both primes.


4



7, 11, 19, 31, 59, 61, 79, 101, 151, 179, 229, 311, 359, 389, 409, 521, 709, 719, 751, 809, 971, 1039, 1061, 1151, 1171, 1201, 1361, 1459, 1481, 1669, 1699, 1811, 1949, 1999, 2131, 2341, 2371, 2411, 2609, 2671, 2711, 2791, 2851, 3019, 3041, 3061, 3119
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..47.


FORMULA

p, 2p9 and 2p+9 all are positive and are primes (hence we omit p=2).


MATHEMATICA

Select[Range[7, 6000], PrimeQ[ # ] && PrimeQ[2# + 9] && PrimeQ[2#  9] &]
okQ[n_]:=Module[{c=2n}, PrimeQ[c+9]&&PrimeQ[c9]]; Select[Prime[ Range[5, 500]], okQ] (* Harvey P. Dale, Apr 25 2011 *)


PROG

(MAGMA) [p: p in PrimesUpTo(3200) IsPrime(2*p+9) and IsPrime(2*p9) ]; // Vincenzo Librandi, Jan 28 2011


CROSSREFS

Sequence in context: A235806 A238501 A133425 * A038984 A165549 A055939
Adjacent sequences: A103799 A103800 A103801 * A103803 A103804 A103805


KEYWORD

nonn


AUTHOR

Zak Seidov, Feb 16 2005


STATUS

approved



