

A045344


Primes congruent to {1, 2} mod 3.


18



2, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307
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OFFSET

1,1


COMMENTS

Same as A045319, except for the 2nd term.  R. J. Mathar, Jan 30 2009
Primes of the form 3*n+1.  JuriStepan Gerasimov, Jan 22 2010
Primes excluding 3.  JuriStepan Gerasimov, Apr 20 2010
Primes p such that p^2 + 2 is composite. 3 is the only prime p such that p^2 + 2 (= 11) is prime. All numbers p^2 + 2 for primes p = 2 and p > 3 are divisible by 3.  Jaroslav Krizek, Nov 25 2013
Primes p satisfying the equation gcd(sigma(p1), p) = 1.  Lechoslaw Ratajczak, Aug 18 2018


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000


FORMULA

a(n) = A000040(A065475(n)).  Reinhard Zumkeller, Dec 17 2009


MATHEMATICA

Select[Prime[Range[150]], MemberQ[{1, 2}, Mod[#, 3]] &] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2012 *)
Drop[Prime@ Range@ 63, {2}] (* Robert G. Wilson v, Jun 04 2015 *)


PROG

(MAGMA) [p: p in PrimesUpTo(740)p mod 3 in {1, 2}] // Vincenzo Librandi, Dec 18 2010
(PARI) a(n)=if(n<2, 2, prime(n+1)) \\ Charles R Greathouse IV, May 13, 2011


CROSSREFS

Cf. A000040, A045372, A045391.
Sequence in context: A118751 A173494 A137519 * A087685 A020619 A165439
Adjacent sequences: A045341 A045342 A045343 * A045345 A045346 A045347


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane


STATUS

approved



