A269705 Numbers k such that prime(k) == 1 (mod 9).

8, 12, 21, 29, 31, 38, 42, 46, 58, 63, 75, 78, 84, 93, 99, 100, 106, 112, 115, 131, 134, 141, 145, 153, 157, 159, 167, 169, 179, 187, 191, 193, 207, 211, 224, 232, 242, 244, 247, 257, 260, 264, 272, 276, 279, 287, 303, 306, 310, 316, 324, 326, 327, 335, 337

Offset: 1

Author

Vincenzo Librandi, Mar 04 2016

Keywords

• nonn

Comments

The asymptotic density of this sequence is 1/6 (by Dirichlet's theorem). - Amiram Eldar, Mar 02 2021

Examples

			a(1) = 8 because prime(8) = 19 and 19 == 1 (mod 9).
		

Crossrefs

The associated primes are in A061237.

Cf. similar sequences listed in A269703.

Programs

Magma

[n: n in [1..500] | NthPrime(n) mod 9 eq 1];

Mathematica

Select[Range[400], Mod[Prime[#], 9] == 1 &]

PARI

lista(nn) = for(n=1, nn, if(Mod(prime(n),9)==1, print1(n, ", "))); \\ Altug Alkan, Mar 04 2016