A141898 Primes congruent to 20 mod 21.
41, 83, 167, 251, 293, 419, 461, 503, 587, 797, 839, 881, 1049, 1091, 1217, 1259, 1301, 1427, 1511, 1553, 1637, 1721, 1847, 1889, 1931, 1973, 2099, 2141, 2267, 2309, 2351, 2393, 2477, 2687, 2729, 2897, 2939, 3023, 3191, 3359, 3527, 3779, 3821, 3863, 3947
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Programs
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GAP
A141898:=Filtered(Filtered([1..10^3],IsPrime),i-> i mod 21 = 20); # Muniru A Asiru, Oct 09 2017
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Magma
[ p: p in PrimesUpTo(5000) | p mod 21 eq 20 ]; // Vincenzo Librandi, Apr 05 2011
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Mathematica
Select[Range[20,5000,21],PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Apr 04 2011*)
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PARI
is(n)=isprime(n) && n%21==20 \\ Charles R Greathouse IV, Jul 02 2016
Formula
a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 02 2016