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A165681
Primes p such that 3*p*(p-1)+1 is not prime.
3
13, 17, 19, 23, 37, 41, 47, 61, 71, 73, 79, 83, 97, 101, 103, 107, 113, 127, 131, 139, 149, 151, 163, 167, 179, 181, 191, 193, 199, 211, 223, 227, 229, 233, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 317, 331, 337, 349, 359, 367, 373, 379, 383, 397, 401
OFFSET
1,1
LINKS
FORMULA
a(n) ~ n log n. - Charles R Greathouse IV, Feb 23 2017
MATHEMATICA
Select[Prime[Range[90]], !PrimeQ[3#(#-1)+1]&] (* Harvey P. Dale, Mar 18 2011 *)
PROG
(PARI) is(n)=isprime(n) && !isprime(3*n*(n-1)+1) \\ Charles R Greathouse IV, Feb 23 2017
CROSSREFS
Sequence in context: A286042 A168447 A191059 * A214033 A268593 A175873
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 24 2009
EXTENSIONS
2 and 3 removed by R. J. Mathar, Sep 26 2009
STATUS
approved