A045472 - OEIS

%I #31 Sep 08 2022 08:44:56

%S 13,29,41,43,71,83,97,113,127,139,167,181,197,211,223,239,251,281,293,

%T 307,337,349,379,419,421,433,449,461,463,491,503,547,587,601,617,631,

%U 643,659,673,701,727,743,757,769

%N Primes congruent to {1, 6} mod 7.

%C Primes p such that p^4 = 1 mod 210. - _Gary Detlefs_, Dec 29 2011

%C Primes in A047336, also in A113801. - _Reinhard Zumkeller_, Jan 07 2012

%H Reinhard Zumkeller, <a href="/A045472/b045472.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) ~ 3n log n. - _Charles R Greathouse IV_, Mar 17 2022

%t Select[Prime[Range[200]],MemberQ[{1,6},Mod[#,7]]&] (* _Vincenzo Librandi_, Aug 13 2012 *)

%o (Haskell)

%o a045472 n = a045472_list !! (n-1)

%o a045472_list = [x | x <- a047336_list, a010051 x == 1]

%o -- _Reinhard Zumkeller_, Jan 07 2012

%o (Magma) [ p: p in PrimesUpTo(1000) | p mod 7 in {1,6} ]; // _Vincenzo Librandi_, Aug 13 2012

%o (PARI) select(p->abs(centerlift(Mod(p,7)))==1, primes(100)) \\ _Charles R Greathouse IV_, Mar 17 2022

%Y Cf. A042989 (complement), A010051.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_