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A153419
Primes p such that p+20 is also prime.
9
3, 11, 17, 23, 41, 47, 53, 59, 83, 89, 107, 131, 137, 173, 179, 191, 251, 257, 263, 293, 311, 317, 347, 353, 359, 389, 401, 419, 443, 467, 479, 503, 521, 557, 587, 593, 599, 641, 653, 719, 809, 839, 857, 863, 887, 947, 971, 977, 1013, 1019, 1031, 1049, 1097
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
EXTENSIONS
Definition improved from Bruno Berselli, Oct 31 2012
STATUS
approved