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A115334 Numbers n such that 3+2n and 3+4n are primes. 9
1, 2, 4, 5, 7, 10, 14, 17, 19, 20, 25, 32, 34, 40, 47, 49, 52, 55, 62, 67, 77, 82, 89, 94, 95, 104, 110, 115, 119, 124, 130, 140, 154, 157, 164, 172, 185, 209, 214, 215, 220, 227, 229, 242, 259, 272, 280, 287, 292, 305, 307, 314, 319, 320, 322, 325, 329, 349, 362 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A206037(n)/2. - Wesley Ivan Hurt, Feb 06 2014

EXAMPLE

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

MATHEMATICA

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

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

PROG

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

CROSSREFS

Cf. A160394. [Klaus Brockhaus, May 14 2009]

Sequence in context: A190235 A023181 A123065 * A167792 A035547 A018598

Adjacent sequences:  A115331 A115332 A115333 * A115335 A115336 A115337

KEYWORD

nonn

AUTHOR

Zak Seidov, Mar 06 2006

STATUS

approved

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Last modified June 16 05:18 EDT 2019. Contains 324145 sequences. (Running on oeis4.)