A216564 Numbers n such that the n-th Lucas number is prime, but cannot be written in the form a^2 + 2*b^2.

7, 19, 31, 79, 5851, 8467, 13963, 574219

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Blair Kelly, Factorizations of Fibonacci and Lucas numbers

Crossrefs

Cf. A000032, A001606.

Sequence in context: A141338 A237366 A216531 * A145042 A153892 A338410

Adjacent sequences: A216561 A216562 A216563 * A216565 A216566 A216567

Keyword

nonn

Author

V. Raman, Sep 08 2012

Status

approved