A141898 Primes congruent to 20 mod 21.

41, 83, 167, 251, 293, 419, 461, 503, 587, 797, 839, 881, 1049, 1091, 1217, 1259, 1301, 1427, 1511, 1553, 1637, 1721, 1847, 1889, 1931, 1973, 2099, 2141, 2267, 2309, 2351, 2393, 2477, 2687, 2729, 2897, 2939, 3023, 3191, 3359, 3527, 3779, 3821, 3863, 3947

Offset

1,1

Links

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

Formula

a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 02 2016

Mathematica

Select[Range[20, 5000, 21], PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Apr 04 2011*)

Prog

(Magma) [ p: p in PrimesUpTo(5000) | p mod 21 eq 20 ]; // Vincenzo Librandi, Apr 05 2011
(PARI) is(n)=isprime(n) && n%21==20 \\ Charles R Greathouse IV, Jul 02 2016
(GAP) A141898:=Filtered(Filtered([1..10^3], IsPrime), i-> i mod 21 = 20); # Muniru A Asiru, Oct 09 2017

Crossrefs

Cf. A000040, A124826.

Sequence in context: A173550 A136072 A098061 * A054998 A067378 A331031

Adjacent sequences: A141895 A141896 A141897 * A141899 A141900 A141901

Keyword

nonn,easy

Author

N. J. A. Sloane, Jul 11 2008

Status

approved