|
| |
|
|
A024892
|
|
Numbers n such that 3*n+1 is prime.
|
|
9
|
|
|
|
2, 4, 6, 10, 12, 14, 20, 22, 24, 26, 32, 34, 36, 42, 46, 50, 52, 54, 60, 64, 66, 70, 74, 76, 80, 90, 92, 94, 102, 104, 110, 112, 116, 122, 124, 126, 132, 136, 140, 144, 146, 152, 154, 162, 166, 174, 180, 182, 190, 192, 200, 202, 204, 206, 210, 214, 220, 224, 230, 236, 242, 244, 246
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
All the primes (with the exception of 3), can be expressed as 3*n+1 or 3*n-1. - César Aguilera, Apr 13 2013
|
|
|
LINKS
|
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
|
|
|
FORMULA
|
a(n) = 2*A024899(n) = A034936(n)+1
|
|
|
MATHEMATICA
|
lst={}; Do[p=3*n+1; If[PrimeQ[p], AppendTo[lst, n]], {n, 0, 10^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 10 2008 *)
Select[Range[250], PrimeQ[3# + 1] &] (* Vincenzo Librandi, Sep 25 2012 *)
|
|
|
PROG
|
(MAGMA) [n: n in [1..1000] | IsPrime(3*n+1)]; // Vincenzo Librandi, Nov 20 2010
|
|
|
CROSSREFS
|
Cf. A002476 (associated primes), A091178 (gives prime index).
Sequence in context: A141104 A047410 A164875 * A087136 A015921 A132631
Adjacent sequences: A024889 A024890 A024891 * A024893 A024894 A024895
|
|
|
KEYWORD
|
nonn,easy
|
|
|
AUTHOR
|
Clark Kimberling
|
|
|
STATUS
|
approved
|
| |
|
|
