|
Search: id:A153261
|
|
|
| A153261 |
|
Primes such that 3*n-2 is not prime. |
|
+0
1
|
|
| 2, 17, 19, 29, 31, 41, 59, 73, 79, 83, 89, 97, 101, 107, 109, 131, 139, 149, 151, 157, 173, 179, 197, 199, 223, 227, 229, 233, 239, 241, 269, 281, 283, 311, 317, 349, 353, 359, 367, 379, 383, 389, 397, 409, 419, 421, 439, 449, 457, 463, 479, 499, 503, 509, 521
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
3*2-2=4 not prime, 17*3-2=49 not prime,... 3*3-2=7 is prime and not in this sequence.
|
|
FORMULA
|
Let p = prime number, all n=(p^2+2)/3 mod (p), or, n=(p^2+6p+2)/3 mod (p) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 01 2009]
|
|
MATHEMATICA
|
lst={}; Do[p=Prime[n]; If[ !PrimeQ[3*p-2], AppendTo[lst, p]], {n, 6!}]; lst
|
|
CROSSREFS
|
Cf. A153184, A153185
Cf. A153238 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 01 2009]
Sequence in context: A133247 A145100 A145101 this_sequence A080115 A119480 A043297
Adjacent sequences: A153258 A153259 A153260 this_sequence A153262 A153263 A153264
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 22 2008
|
|
|
Search completed in 0.002 seconds
|
