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A252090
Primes p such that p + 28 is also prime.
5
3, 13, 19, 31, 43, 61, 73, 79, 103, 109, 139, 151, 163, 199, 211, 223, 229, 241, 283, 331, 373, 421, 433, 439, 463, 541, 571, 613, 619, 631, 673, 691, 733, 769, 811, 829, 853, 859, 883, 919, 991, 1021, 1033, 1063, 1069, 1123, 1153, 1201, 1231, 1249
OFFSET
1,1
LINKS
EXAMPLE
19 is in the sequence because 19 is prime and 19 + 28 = 47 is also prime.
433 is in the sequence because 433 is prime and 433 + 28 = 461 is also prime.
MAPLE
P:= select(isprime, {seq(2*i+1, i=1..10000)}):
P intersect map(`-`, P, 28);
# if using Maple 11 or earlier, uncomment the next line
# sort(convert(%, list)); # Robert Israel, Dec 14 2014
MATHEMATICA
Select[Prime[Range[250]], PrimeQ[# + 28] &]
PROG
(Magma) [NthPrime(n): n in [1..250] | IsPrime(NthPrime(n)+28)];
(PARI) is(n)=isprime(n)&&isprime(n+28) \\ Anders Hellström, Dec 01 2015
CROSSREFS
Sequence in context: A045435 A038974 A168425 * A079419 A117300 A023215
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 14 2014
STATUS
approved