A045326 - OEIS

A045326

Primes congruent to {2, 3} mod 4.

2, 3, 7, 11, 19, 23, 31, 43, 47, 59, 67, 71, 79, 83, 103, 107, 127, 131, 139, 151, 163, 167, 179, 191, 199, 211, 223, 227, 239, 251, 263, 271, 283, 307, 311, 331, 347, 359, 367, 379, 383, 419, 431, 439, 443, 463, 467, 479, 487, 491, 499, 503, 523, 547, 563, 571, 587, 599, 607, 619

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Apart from initial term 2, same as A002145 (primes of the form 4k+3).

Primes not in A002144. - Juri-Stepan Gerasimov, Oct 16 2010

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000 (first 1000 terms from Vincenzo Librandi)

FORMULA

a(n) ~ 2n log n. - Charles R Greathouse IV, Dec 11 2016

MATHEMATICA

Select[Prime[Range[120]], MemberQ[{2, 3}, Mod[#, 4]] &] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2012 *)

PROG

(Magma) [p: p in PrimesUpTo(740) | p mod 4 in [2, 3]] // Vincenzo Librandi, Dec 18 2010

(PARI) is(n)=n%4>1 && isprime(n) \\ Charles R Greathouse IV, Dec 11 2016

(Python)

from itertools import count, islice

from sympy import prime

def A045326_gen(): # generator of terms

return filter(lambda n:n>>1&1, map(prime, count(1)))

A045326_list = list(islice(A045326_gen(), 20)) # Chai Wah Wu, Jun 23 2023

CROSSREFS

Sequence in context: A108541 A038937 A092940 * A214029 A195602 A105897

Adjacent sequences: A045323 A045324 A045325 * A045327 A045328 A045329

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved