A296020 Number of primes of the form 4*k+3 <= 4*n+3.

1, 2, 3, 3, 4, 5, 5, 6, 6, 6, 7, 8, 8, 8, 9, 9, 10, 11, 11, 12, 13, 13, 13, 13, 13, 14, 15, 15, 15, 15, 15, 16, 17, 17, 18, 18, 18, 19, 19, 19, 20, 21, 21, 21, 22, 22, 22, 23, 23, 24, 24, 24, 25, 25, 25, 26, 27, 27, 27, 28, 28, 28, 29, 29, 29, 30, 30, 31, 31, 31

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Mathematica

Module[{nn=300, pr3}, pr3=Table[If[PrimeQ[k]&&Mod[k, 4]==3, 1, 0], {k, 0, nn}]; Table[Total[Take[pr3, 4n+3]], {n, (nn-3)/4}]] (* Harvey P. Dale, Aug 10 2019 *)

Prog

(Ruby)
require 'prime'
def A(k, n)
  ary = []
  cnt = 0
  k.step(4 * n + k, 4){|i|
    cnt += 1 if i.prime?
    ary << cnt
  }
  ary
end
p A(3, 100)

Crossrefs

Cf. A004767, A091099, A295996, A296021.

Sequence in context: A094606 A080595 A302779 * A266350 A123579 A166493

Adjacent sequences: A296017 A296018 A296019 * A296021 A296022 A296023

Keyword

nonn

Author

Seiichi Manyama, Dec 02 2017

Status

approved