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A222961 Numbers n such that 2*n + {3, 5, 9, 11, 15, 21} are all primes. 1
1, 4, 739, 82849, 163069, 330544, 511249, 534349, 623179, 730699, 958864, 1529434, 2077954, 2109139, 2763499, 4172074, 5067199, 5882524, 5950249, 6532159, 7860409, 7880044, 9252184, 9368419, 9564769, 9605719, 10024984 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

After 1, a(n) is congruent to 4 or 9 (mod 10), this means that a(n) is of the form 5k-1. Clearly, each term is not divisible by 3, 7 and 11.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

MATHEMATICA

Select[Range[7000000], Union[PrimeQ[2 # +{3, 5, 9, 11, 15, 21}]]=={True}&]

PROG

(MAGMA) [n: n in [1..11000000] | forall{2*n+k: k in [3, 5, 9, 11, 15, 21] | IsPrime(2*n+k)}];

CROSSREFS

Cf. A136162.

Sequence in context: A134579 A090588 A053986 * A160737 A128846 A195625

Adjacent sequences:  A222958 A222959 A222960 * A222962 A222963 A222964

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Mar 13 2013

STATUS

approved

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Last modified March 26 06:48 EDT 2019. Contains 321481 sequences. (Running on oeis4.)