A124826 Primes congruent to 1 mod 21.

43, 127, 211, 337, 379, 421, 463, 547, 631, 673, 757, 883, 967, 1009, 1051, 1093, 1303, 1429, 1471, 1597, 1723, 1933, 2017, 2143, 2269, 2311, 2437, 2521, 2647, 2689, 2731, 2857, 3067, 3109, 3319, 3361, 3529, 3571, 3613, 3697, 3739, 3823, 3907, 4159, 4201

Offset: 1

Author

N. J. A. Sloane, Jul 11 2008

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A000040, A141881.

Programs

Magma

[p: p in PrimesUpTo(5000) | p mod 21 eq 1 ]; // Vincenzo Librandi, Aug 14 2012

Mathematica

Select[Range[1,5000,21],PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Apr 03 2011*)

PARI

is(n)=isprime(n) && n%21==1 \\ Charles R Greathouse IV, Jul 01 2016