%I #9 Sep 08 2022 08:45:35
%S 31,71,151,191,271,311,431,631,751,911,991,1031,1151,1231,1471,1511,
%T 1831,1871,1951,2111,2311,2351,2551,2591,2671,2711,2791,3191,3271,
%U 3391,3511,3631,3671,3911,4111,4231,4271,4391,4591,4751,4831,4871,4951,5231,5351
%N Primes congruent to 31 mod 40.
%H Vincenzo Librandi, <a href="/A142195/b142195.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) ~ 16n log n. - _Charles R Greathouse IV_, Jul 03 2016
%t Select[Prime[Range[2000]],MemberQ[{31},Mod[#,40]]&] (* _Vincenzo Librandi_, Aug 22 2012 *)
%o (Magma) [p: p in PrimesUpTo(7000) | p mod 40 eq 31 ]; // _Vincenzo Librandi_, Aug 22 2012
%o (PARI) is(n)=isprime(n) && n%40==31 \\ _Charles R Greathouse IV_, Jul 03 2016
%Y Cf. A000040.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_, Jul 11 2008