A141948 Primes congruent to 1 mod 27.

109, 163, 271, 379, 433, 487, 541, 757, 811, 919, 1297, 1459, 1567, 1621, 1783, 1999, 2053, 2161, 2269, 2377, 2539, 2593, 2647, 2917, 2971, 3079, 3187, 3457, 3511, 3673, 3727, 3889, 3943, 4051, 4159, 4483, 4591, 4861, 4969, 5023, 5077, 5347, 5563, 5779

Offset: 1

Author

N. J. A. Sloane, Jul 11 2008

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040.

Programs

Magma

[p: p in PrimesUpTo(7000) | p mod 27 eq 1 ]; // Vincenzo Librandi, Aug 16 2012

Mathematica

Select[Prime[Range[800]], MemberQ[{1}, Mod[#, 27]] &] (* Vincenzo Librandi, Aug 16 2012 *)
Select[Range[1,6000,27],PrimeQ] (* Harvey P. Dale, Jan 16 2023 *)

PARI

is(n)=isprime(n) && n%27==1 \\ Charles R Greathouse IV, Jul 02 2016

Formula

a(n) ~ 18n log n. - Charles R Greathouse IV, Jul 02 2016