

A087370


Numbers n such that 3n  1 is a prime.


12



1, 2, 4, 6, 8, 10, 14, 16, 18, 20, 24, 28, 30, 34, 36, 38, 44, 46, 50, 56, 58, 60, 64, 66, 76, 78, 80, 84, 86, 88, 90, 94, 98, 104, 106, 116, 118, 120, 128, 130, 134, 140, 144, 148, 150, 154, 156, 160, 164, 168, 170, 174, 186, 188, 190, 196, 198, 200, 206, 214, 216
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OFFSET

1,2


COMMENTS

3*n  1 is an Eisenstein prime.  Vincenzo Librandi, Aug 08 2010


REFERENCES

M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


FORMULA

a(n)= A024893(n) + 1 = A088879(n) + 2.


MATHEMATICA

lst={}; Do[p=3*n1; If[PrimeQ[p], AppendTo[lst, n]], {n, 0, 10^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)


PROG

(Haskell)
a087370 n = a087370_list !! (n1)
a087370_list = filter ((== 1) . a010051' . subtract 1 . (* 3)) [0..]
 Reinhard Zumkeller, Jul 03 2015


CROSSREFS

A003627 gives primes, A091177 gives prime index.
Cf. A010051, subsequence of A016789, A259645.
Sequence in context: A260391 A022292 A225241 * A138929 A334169 A180081
Adjacent sequences: A087367 A087368 A087369 * A087371 A087372 A087373


KEYWORD

easy,nonn


AUTHOR

Giovanni Teofilatto, Oct 21 2003


EXTENSIONS

Corrected and extended by Ray Chandler, Oct 22 2003


STATUS

approved



