A215918 Numbers n such that 6*n + {1, 5, 7} are all primes.
1, 2, 6, 11, 16, 17, 32, 37, 46, 51, 76, 102, 137, 142, 146, 181, 216, 237, 241, 247, 277, 282, 297, 311, 312, 332, 347, 356, 396, 447, 451, 466, 527, 542, 576, 577, 641, 692, 752, 797, 871, 902, 906, 941, 942, 956, 1091, 1137, 1201, 1292, 1312, 1381, 1437
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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Magma
[n: n in [1..1000] | forall{6*n+r: r in [1,5,7] | IsPrime(6*n+r)}]; // Bruno Berselli, Aug 27 2012 -
Mathematica
Select[Range[1437], Union[PrimeQ[6 # + {1, 5, 7}]] == {True} &] (* T. D. Noe, Aug 27 2012 *) -
PARI
for(n=1,2000,if(isprime(6*n+1)&&isprime(6*n+5)&&isprime(6*n+7),print(n",")))
Formula
a(n) = (A022005(n)-1)/6.
Comments