A222961 Numbers n such that 2*n + {3, 5, 9, 11, 15, 21} are all primes.

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

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 A332174

Adjacent sequences: A222958 A222959 A222960 * A222962 A222963 A222964

Keyword

nonn

Author

Vincenzo Librandi, Mar 13 2013

Status

approved