A142160 Primes congruent to 2 mod 39.

2, 41, 197, 353, 431, 509, 587, 743, 821, 977, 1289, 1367, 1523, 1601, 1913, 2069, 2381, 2459, 2693, 2927, 3083, 3863, 4019, 4253, 4409, 4643, 4721, 4799, 4877, 5189, 5501, 5657, 5813, 6047, 6203, 6359, 6827, 6983, 7451, 7529, 7607, 7841, 7919, 8231, 8387

Offset

1,1

Comments

a(4)..a(7) are the first set of 4 prime-indexed primes in arithmetic progression: a(4) = 353 = prime(prime(20)); a(5) = 431 = prime(prime(23)); a(6) = 509 = prime(prime(25)); a(7) = 587 = prime(prime(28)). Then we can see that 431-353 = 509-431 = 587-509 = 78. - Bobby Jacobs, Nov 30 2016

Links

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

Formula

a(n) ~ 24n log n. - Charles R Greathouse IV, Jul 03 2016

Mathematica

Select[Prime[Range[3000]], MemberQ[{2}, Mod[#, 39]]&] (* Vincenzo Librandi, Aug 19 2012 *)
Select[Range[2, 9000, 39], PrimeQ] (* Harvey P. Dale, Oct 21 2014 *)

Prog

(Magma)[p: p in PrimesUpTo(9000) | p mod 39 eq 2 ]; // Vincenzo Librandi, Aug 19 2012
(PARI) is(n)=isprime(n) && n%39==2 \\ Charles R Greathouse IV, Jul 03 2016

Crossrefs

Cf. A000040.

Sequence in context: A287335 A212837 A063271 * A174615 A109125 A037061

Adjacent sequences: A142157 A142158 A142159 * A142161 A142162 A142163

Keyword

nonn,easy

Author

N. J. A. Sloane, Jul 11 2008

Status

approved