A141885 Primes congruent to 13 mod 20.

13, 53, 73, 113, 173, 193, 233, 293, 313, 353, 373, 433, 593, 613, 653, 673, 733, 773, 853, 953, 1013, 1033, 1093, 1153, 1193, 1213, 1373, 1433, 1453, 1493, 1553, 1613, 1693, 1733, 1753, 1873, 1913, 1933, 1973, 1993, 2053, 2113, 2153, 2213, 2273, 2293, 2333, 2393

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, A105854, A141881, A141882, A141883.

Programs

Magma

[p: p in PrimesUpTo(3000) | p mod 20 eq 13 ]; // Vincenzo Librandi, Aug 16 2012

Mathematica

Select[Range[13,5000,20],PrimeQ[#]&] (* Vladimir Joseph Stephan Orlovsky, Mar 31 2011*)

PARI

is(n)=isprime(n) && n%20==13 \\ Charles R Greathouse IV, Jul 02 2016

Formula

a(n) ~ 8n log n. - Charles R Greathouse IV, Jul 02 2016