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 A115334 Numbers n such that 3+2n and 3+4n are primes. 9

%I

%S 1,2,4,5,7,10,14,17,19,20,25,32,34,40,47,49,52,55,62,67,77,82,89,94,

%T 95,104,110,115,119,124,130,140,154,157,164,172,185,209,214,215,220,

%U 227,229,242,259,272,280,287,292,305,307,314,319,320,322,325,329,349,362

%N Numbers n such that 3+2n and 3+4n are primes.

%H Vincenzo Librandi, <a href="/A115334/b115334.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A206037(n)/2. - _Wesley Ivan Hurt_, Feb 06 2014

%e 5 is in the sequence because 3 + 2*5 = 13 and 3 + 4*5 = 23 are both prime.

%t Do[If[PrimeQ[{3+2d,3+4d}]=={True,True},Print[d]],{d,100000}]

%t Select[Range[400],And@@PrimeQ[{3+2#,3+4#}]&] (* _Harvey P. Dale_, Sep 02 2013 *)

%o (MAGMA) [ n: n in [1..365] | IsPrime(3+2*n) and IsPrime(3+4*n) ]; \\ _Klaus Brockhaus_, May 14 2009

%Y Cf. A160394. [_Klaus Brockhaus_, May 14 2009]

%K nonn

%O 1,2

%A _Zak Seidov_, Mar 06 2006

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Last modified August 8 14:04 EDT 2020. Contains 336298 sequences. (Running on oeis4.)