A061241 Prime numbers == 7 (mod 9).

7, 43, 61, 79, 97, 151, 223, 241, 277, 313, 331, 349, 367, 421, 439, 457, 547, 601, 619, 673, 691, 709, 727, 853, 907, 997, 1033, 1051, 1069, 1087, 1123, 1213, 1231, 1249, 1303, 1321, 1429, 1447, 1483, 1609, 1627, 1663, 1699, 1753, 1789, 1861, 1879, 1933

Offset: 1

Author

Amarnath Murthy, Apr 23 2001

Keywords

• nonn
• easy

Comments

A010888(a(n)) = 7. - Reinhard Zumkeller, Feb 25 2005

Links

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

Crossrefs

Cf. A061237..A061242.

Programs

Magma

[p: p in PrimesUpTo(2000) | p mod 9 eq 7]; // Vincenzo Librandi, Dec 25 2010

Maple

select(isprime,[seq(9*i+7,i=0..10^5)]); # Robert Israel, Apr 20 2014

Mathematica

Select[Range[2500], PrimeQ[#] && Mod[#, 9] == 7 &]
Select[Prime[Range[300]], Mod[#, 9] == 7 & ] (* Harvey P. Dale, Apr 30 2011 *)

PARI

select(n->n%9==7, primes(400)) \\ Charles R Greathouse IV, May 27 2014

Formula

a(n) ~ 6n log n. - Charles R Greathouse IV, May 14 2025

Extensions

More terms from Robert G. Wilson v, May 10 2001