

A096447


Odd primes p such that the number of primes less than p equal to 1 mod 4 is equal to the number of primes less than p equal to 3 mod 4.


18



3, 7, 19, 43, 463, 26839, 26861, 26879, 26891, 26903, 26927, 616783, 616799, 616841, 616849, 616877, 617039, 617269, 617369, 617401, 617429, 617453, 617471, 617479, 617521, 617537, 617587, 617689, 617717, 617723, 618439, 618547, 618619, 618643
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

First term prime(2) = 3 is placed on 0th row.
If prime(n1) = +1 mod 4 is on kth row then we put prime(n) on (k1)st row.
If prime(n1) = 1 mod 4 is on kth row then we put prime(n) on (k+1)st row.
This process makes an array of prime numbers:
3, 7, 19, 43, ....0th row (this sequence)
5, 11, 17, 23, 31, 41, 47, 59, 67, 103, 127, .... first row (A096448)
13, 29, 37, 53, 61, 71, 79, 101, 107, 113 .... 2nd row (A096451)
73, 83, 97, 109, .... 3rd row
89, .... 4th row
This is the next prime after A007351.  Joshua Zucker, May 03 2006


LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000


MATHEMATICA

lim = 10^5; k1 = 0; k3 = 0; p = 2; t = {}; Do[p = NextPrime[p]; If[k1 == k3, AppendTo[t, p]]; If[Mod[p, 4] == 1, k1++, k3++], {lim}]; t (* T. D. Noe, Sep 07 2011 *)


CROSSREFS

Cf. A096448A096455.
Cf. A007351, A096448A096455.
Sequence in context: A136041 A146685 A146653 * A274596 A185696 A141344
Adjacent sequences: A096444 A096445 A096446 * A096448 A096449 A096450


KEYWORD

nonn,easy


AUTHOR

Yasutoshi Kohmoto, Aug 12 2004


EXTENSIONS

More terms from Joshua Zucker, May 03 2006
Added "odd" to definition.  N. J. A. Sloane, Sep 09 2015


STATUS

approved



