OFFSET
1,1
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000 (first 1000 terms from Vincenzo Librandi)
EXAMPLE
3 is in the sequence because 3+20=23 is prime; 11 is in the sequence because 11+20=31 is prime.
MAPLE
for a from 1 to 140 do if isprime(a) and isprime(a+20) then print(a)
end if; end do; # Matt C. Anderson, Jun 20 2022
MATHEMATICA
Select[Prime[Range[200]], PrimeQ[(# + 20)]&] (* Vincenzo Librandi, Apr 14 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(1100) | IsPrime(p + 20)]; // Vincenzo Librandi, Apr 14 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Dec 25 2008
EXTENSIONS
Definition improved from Bruno Berselli, Oct 31 2012
STATUS
approved