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A257483
Primes p such that (p mod 8) = (p mod 27).
2
2, 3, 5, 7, 223, 433, 439, 653, 1087, 1297, 1301, 1303, 1733, 1949, 1951, 2161, 2377, 2381, 2383, 2593, 3457, 3461, 3463, 3673, 3677, 3889, 4111, 4327, 4759, 4969, 4973, 5189, 5407, 5623, 5839, 6053, 6269, 6271, 6481, 6701, 6703, 6917, 7129, 7349, 7351, 7561
OFFSET
1,1
COMMENTS
a(n) is 2, 3 or of the form 216k + r where r is in {1, 5, 7} - David A. Corneth, May 26 2015
LINKS
FORMULA
a(n) = A000040(A257482(n)).
a(n) ~ 24n log n. - Charles R Greathouse IV, May 26 2015
EXAMPLE
223 == 7 (mod 8) == 7 (mod 27), 433 == 1 (mod 8) == 1 (mod 27).
MAPLE
select(isprime, [2, 3, seq(seq(216*k+r, r=[1, 5, 7]), k=0..1000)]); # Robert Israel, May 26 2015
MATHEMATICA
Select[Prime@ Range@ 1000, Mod[#, 8] == Mod[#, 27] &] (* Michael De Vlieger, Apr 27 2015 *)
PROG
(Magma) [p: p in PrimesUpTo(8000) | p mod 8 eq p mod 27]; // Vincenzo Librandi, Apr 28 2015
(PARI) is(n)=my(k=n%216); (k==1||k==5||k==7) && isprime(n) \\ Charles R Greathouse IV, May 26 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Apr 26 2015
STATUS
approved