A248409 Least prime of the form x^2+13*n^2.

13, 53, 181, 233, 389, 757, 641, 857, 1069, 1301, 1609, 1873, 2213, 2549, 3121, 3329, 3761, 4261, 4729, 5209, 5737, 6301, 6977, 7489, 8161, 8837, 9733, 10193, 10937, 11701, 12497, 13313, 14173, 15053, 16069, 17137, 18121, 18773, 19777, 20809, 21997, 23053, 24137, 25169, 27109, 27509

Offset

1,1

Comments

Subsequence of A033210 (Primes of the form x^2+13*y^2).

Links

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Example

a(1)=13 because the least prime of the form x^2+13*1^2 is 13 (at x=0).
a(100)=130121 because the least prime of the form x^2+13*100^2 is 130121 (at x=11).
a(200)=520361 because the least prime of the form x^2+13*200^2 is 520361 (at x=19).

Prog

(PARI) a(n) = {x = 0; while (!isprime(p=x^2+13*n^2), x++); p; } \\ Michel Marcus, Oct 06 2014

Crossrefs

Cf. A033210, A106856, A247881, A248221.

Sequence in context: A179549 A139974 A142188 * A206444 A156156 A201486

Adjacent sequences: A248406 A248407 A248408 * A248410 A248411 A248412

Keyword

nonn

Author

Zak Seidov, Oct 06 2014

Status

approved