A087370 - OEIS

A087370

Numbers n such that 3n - 1 is a prime.

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

For all elements of this sequence there are no pairs (x,y) of positive integers such that a(n) = 3*x*y - x + y. - Pedro Caceres, Jan 28 2021

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