OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
a(n) ~ 46n log n. - Charles R Greathouse IV, Jul 03 2016
MATHEMATICA
Select[Prime[Range[2500]], MemberQ[{20}, Mod[#, 47]]&] (* Vincenzo Librandi, Aug 27 2012 *)
Select[Range[20, 16000, 47], PrimeQ] (* Harvey P. Dale, Jun 01 2018 *)
PROG
(Magma) [p: p in PrimesUpTo(18000) | p mod 47 eq 20]; // Vincenzo Librandi, Aug 27 2012
(PARI) is(n)=isprime(n) && n%47==20 \\ Charles R Greathouse IV, Jul 03 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jul 11 2008
STATUS
approved