A141884 - OEIS

%I #14 Sep 08 2022 08:45:35

%S 11,31,71,131,151,191,211,251,271,311,331,431,491,571,631,691,751,811,

%T 911,971,991,1031,1051,1091,1151,1171,1231,1291,1451,1471,1511,1531,

%U 1571,1811,1831,1871,1931,1951,2011,2111,2131,2251,2311,2351,2371,2411,2531,2551

%N Primes congruent to 11 mod 20.

%H Vincenzo Librandi, <a href="/A141884/b141884.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) ~ 8n log n. - _Charles R Greathouse IV_, Jul 03 2016

%t Select[Range[11,5000,20],PrimeQ[#]&] (* _Vladimir Joseph Stephan Orlovsky_, Mar 31 2011*)

%t Select[Prime[Range[400]],Mod[#,20]==11&] (* _Harvey P. Dale_, Aug 10 2021 *)

%o (Magma) [p: p in PrimesUpTo(3000) | p mod 20 eq 11 ]; // _Vincenzo Librandi_, Aug 16 2012

%o (PARI) is(n)=isprime(n) && n%20==11 \\ _Charles R Greathouse IV_, Jul 03 2016

%Y Cf. A000040, A105854, A141881, A141882, A141883.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_, Jul 11 2008