OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) ~ 12n log n. - Charles R Greathouse IV, Jul 02 2016
MATHEMATICA
Select[Range[20, 5000, 21], PrimeQ] (* Vladimir Joseph Stephan Orlovsky, Apr 04 2011*)
PROG
(Magma) [ p: p in PrimesUpTo(5000) | p mod 21 eq 20 ]; // Vincenzo Librandi, Apr 05 2011
(PARI) is(n)=isprime(n) && n%21==20 \\ Charles R Greathouse IV, Jul 02 2016
(GAP) A141898:=Filtered(Filtered([1..10^3], IsPrime), i-> i mod 21 = 20); # Muniru A Asiru, Oct 09 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jul 11 2008
STATUS
approved