A216569 Numbers n such that the n-th Fibonacci number is prime and can be written in the form a^2 + 6*b^2.

23, 47, 359, 431, 433, 9311, 25561, 35999, 37511, 50833, 81839, 590041, 593689, 1285607, 1636007, 1968721

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Blair Kelly, Factorizations of Fibonacci and Lucas numbers

Mathematica

Select[Range[2*10^6], PrimeQ[Fibonacci[#]]&&FindInstance[a^2+6b^2==Fibonacci[#], {a, b}, Integers]!={}&] (* Harvey P. Dale, Sep 18 2019 *)

Crossrefs

Cf. A000045, A001605.

Intersection of A005478 and A155716.

Sequence in context: A052229 A054203 A247673 * A042054 A084667 A255596

Adjacent sequences: A216566 A216567 A216568 * A216570 A216571 A216572

Keyword

nonn

Author

V. Raman, Sep 08 2012

Status

approved