A346145 Primes of the form k^2 + 25.

29, 41, 61, 89, 281, 349, 509, 601, 701, 809, 1049, 1181, 1321, 1789, 2141, 2729, 3389, 4649, 5209, 5501, 5801, 8861, 9241, 9629, 10429, 11261, 11689, 12569, 15401, 15901, 17449, 17981, 18521, 19069, 21341, 21929, 23741, 24989, 26921, 27581, 33149, 39229, 40829, 41641, 42461, 45821, 46681, 52009

Offset

1,1

Comments

k^2 + 25 = (k+5i)*(k-5i), where i is the imaginary unit.

Links

Table of n, a(n) for n=1..48.

Todor Szimeonov, A dramatic encounter

Formula

a(n) >> n log^2 n (Brun sieve). - Charles R Greathouse IV, Jul 06 2021

Mathematica

Select[Range[230]^2 + 25, PrimeQ] (* Amiram Eldar, Jul 06 2021 *)

Prog

(PARI) list(lim)=my(v=List(), p); forstep(k=2, sqrtint(lim\1-25), 2, if(isprime(p = k^2+25), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Jul 06 2021

Crossrefs

Cf. A002144, A002496, A005473, A138353, A243451.

Sequence in context: A216815 A157141 A107218 * A058900 A137226 A057539

Adjacent sequences: A346142 A346143 A346144 * A346146 A346147 A346148

Keyword

nonn

Author

Todor Szimeonov, Jul 06 2021

Status

approved