

A030433


Primes of form 10n+9.


27



19, 29, 59, 79, 89, 109, 139, 149, 179, 199, 229, 239, 269, 349, 359, 379, 389, 409, 419, 439, 449, 479, 499, 509, 569, 599, 619, 659, 709, 719, 739, 769, 809, 829, 839, 859, 919, 929, 1009, 1019, 1039, 1049, 1069, 1109, 1129, 1229, 1249, 1259, 1279, 1289
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OFFSET

1,1


COMMENTS

Also primes of form 5n+4.
5 is quadratic residue of primes of form 10*n1.  Vincenzo Librandi, Jun 25 2014
Also, primes p such that 5 divides sigma(p), cf. A274397.  M. F. Hasler, Jul 10 2016


LINKS

Michael B. Porter, Table of n, a(n) for n = 0..100000
A. Granville and G. Martin, Prime number races, arXiv:math/0408319 [math.NT], 2004.
Erika Klarreich, Mathematicians Discover Prime Conspiracy, Quanta Magazine, 2016.
R. J. Lemke Oliver and K. Soundararajan, Unexpected biases in the distribution of consecutive primes, arXiv:1603.03720 [math.NT], 2016.


FORMULA

a(n) = 10*A102700(n) + 9.
Union of A132234 and A132236.  Ray Chandler, Apr 07 2009


MATHEMATICA

Select[Prime@Range[210], Mod[ #, 10] == 9 &] (* Ray Chandler, Nov 07 2006 *)
Select[Range[9, 1300, 10], PrimeQ] (* Harvey P. Dale, Jun 01 2012 *)


PROG

(PARI) select(n>n%10==9, primes(100)) \\ Charles R Greathouse IV, Apr 29 2015


CROSSREFS

Cf. A045457, A049510, A102700.
Sequence in context: A084666 A242265 A004618 * A242550 A141311 A090148
Adjacent sequences: A030430 A030431 A030432 * A030434 A030435 A030436


KEYWORD

nonn


AUTHOR

Warut Roonguthai


EXTENSIONS

Extended by Ray Chandler, Nov 07 2006


STATUS

approved



