A255634 Numbers n such that 1 + 16n^2 is prime.

1, 4, 5, 6, 9, 10, 14, 21, 29, 30, 31, 39, 40, 44, 45, 46, 51, 56, 59, 60, 64, 65, 66, 70, 71, 75, 85, 96, 99, 100, 105, 109, 110, 111, 116, 124, 134, 136, 139, 144, 146, 159, 161, 170, 174, 175, 176, 179, 185, 190, 191, 195, 196, 204, 215, 216, 230, 234, 240, 251, 259, 265, 270, 274, 281

Offset

1,2

Comments

Note the sets of 3 consecutive numbers starting with 4, 29, 44, 64, 109, 174, ..., these numbers are congruent to 4 mod 5; cf. A255635.

Links

Table of n, a(n) for n=1..65.

Maple

A255634:=n->`if`(isprime(1+16*n^2), n, NULL): seq(A255634(n), n=1..300); # Wesley Ivan Hurt, Feb 28 2015

Mathematica

Select[Range[400], PrimeQ[16 #^2 + 1] &] (* Vincenzo Librandi, Mar 03 2015 *)

Prog

(PARI) select(n->isprime(1+16*n^2), vector(300, n, n)) \\ Colin Barker, Mar 01 2015
(Magma) [n: n in [0..300] | IsPrime(16*n^2+1)]; // Vincenzo Librandi, Mar 03 2015

Crossrefs

Cf. A001912, A005574, A255635.

Sequence in context: A223138 A287676 A082812 * A075903 A029942 A162016

Adjacent sequences: A255631 A255632 A255633 * A255635 A255636 A255637

Keyword

nonn

Author

Zak Seidov, Feb 28 2015

Status

approved