A086381 Numbers n such that p=n^2+2 and p+2 are primes.

1, 3, 15, 33, 45, 57, 117, 147, 243, 255, 303, 375, 423, 447, 453, 477, 573, 753, 837, 897, 903, 1035, 1497, 1905, 2055, 2085, 2193, 2283, 2433, 2487, 2535, 2583, 2757, 2823, 2943, 2955, 3003, 3213, 3285, 3345, 3603, 3657, 3687, 4407, 4575, 4977, 5037, 5043, 5325, 5355, 5367, 5403, 5727

Offset

1,2

Comments

The twin primes are given by A253639 and A085554. Except for the initial term, all a(n)=3 (mod 6). - M. F. Hasler, Jan 16 2015

Links

M. F. Hasler, Table of n, a(n) for n = 1..10000

Formula

Intersection of A067201 and A007591. - M. F. Hasler, Jan 19 2015

Prog

(Magma)[n: n in [0..10000]|IsPrime(n^2+2) and IsPrime(n^2+4)] // Vincenzo Librandi, Dec 16 2010
(PARI) is_A086381(x)=ispseudoprime(x^2+2)&&ispseudoprime(x^2+4)
forstep(x=1, 9999, 2, is_A086381(x)&&print1(x", ")) \\ M. F. Hasler, Jan 16 2015

Crossrefs

Cf. A253639, A085554, A059100, A087475.

Sequence in context: A358804 A152813 A184235 * A031091 A211441 A086380

Adjacent sequences: A086378 A086379 A086380 * A086382 A086383 A086384

Keyword

easy,nonn

Author

Zak Seidov, Sep 07 2003

Extensions

More terms from Vincenzo Librandi, Dec 16 2010

Status

approved