A269704 Numbers k such that prime(k) == 1 (mod 8).

7, 13, 21, 24, 25, 30, 33, 44, 51, 53, 55, 60, 65, 68, 71, 79, 80, 84, 87, 88, 98, 104, 106, 108, 110, 113, 116, 122, 135, 136, 140, 148, 152, 158, 159, 162, 165, 169, 174, 176, 184, 189, 191, 196, 197, 199, 204, 209, 211, 216, 218, 223, 227, 234, 237, 245

Offset: 1

Author

Vincenzo Librandi, Mar 04 2016

Keywords

• nonn

Comments

The asymptotic density of this sequence is 1/4 (by Dirichlet's theorem). - Amiram Eldar, Mar 01 2021

Examples

			a(1) = 7 because prime(7) = 17 and 17 == 1 (mod 8).
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

The associated primes are in A007519.

Cf. similar sequences listed in A269703.

Programs

Magma

[n: n in [1..500] | NthPrime(n) mod 8 eq 1];

Maple

Res:= NULL: count:= 0:
p:= 2:
for n from 2 while count < 100 do
  p:= nextprime(p);
  if p mod 8 = 1 then count:= count+1; Res:= Res, n fi
od:
Res; # Robert Israel, May 06 2019

Mathematica

Select[Range[300], Mod[Prime[#], 8] == 1 &]

PARI

lista(nn) = for(n=1, nn, if(Mod(prime(n),8)==1, print1(n, ", "))); \\ Altug Alkan, Mar 04 2016