A270818 Prime numbers of the form (2^k + k^2)/3.

19, 59, 43787, 11185019, 2932031008019, 768614336404565891, 3148244321913096810907, 1177898043185589553055531667161945677218322597917079305414404134195099211

Offset

1,1

Comments

The corresponding values of k are 5, 7, 17, 25, 43, 61, 73, 241, 739, 833, 1297, 1981, 4211, 4501, 7739, 8141, 24965, ... - Amiram Eldar, Mar 07 2020

Links

Amiram Eldar, Table of n, a(n) for n = 1..12

José Camacho Medina's Matematico Fresnillense, Nueva Fórmula Generadora de Números Primos: Función Camila (in Spanish).

Mathematica

Select[Table[(2^n + n^2)/3, {n, 1, 1000}], PrimeQ]

Prog

(PARI) forstep(n=5, 1e3, [2, 4], if(isprime(t=(2^n+n^2)/3), print1(t", "))) \\ Charles R Greathouse IV, Apr 07 2016

Crossrefs

Cf. A000043, A057468.

Sequence in context: A139981 A235705 A171247 * A206426 A211145 A338990

Adjacent sequences: A270815 A270816 A270817 * A270819 A270820 A270821

Keyword

nonn

Author

José de Jesús Camacho Medina, Apr 07 2016

Status

approved