A141882 - OEIS

%I #14 Jan 08 2023 11:39:16

%S 7,47,67,107,127,167,227,307,347,367,467,487,547,587,607,647,727,787,

%T 827,887,907,947,967,1087,1187,1307,1327,1367,1427,1447,1487,1567,

%U 1607,1627,1667,1747,1787,1847,1867,1907,1987,2027,2087,2207,2267,2287,2347,2447

%N Primes congruent to 7 mod 20.

%H Vincenzo Librandi, <a href="/A141882/b141882.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[7,5000,20],PrimeQ[#]&] (* _Vladimir Joseph Stephan Orlovsky_, Mar 31 2011*)

%t Select[Prime[Range[400]],Mod[#,20]==7&] (* _Harvey P. Dale_, Jan 08 2023 *)

%o (Magma) [p: p in PrimesUpTo(3000) | p mod 20 eq 7 ]; // _Vincenzo Librandi_, Aug 16 2012

%o (PARI) is(n)=isprime(n) && n%20==7 \\ _Charles R Greathouse IV_, Jul 01 2016

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

%K nonn,easy

%O 1,1

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