A216570 - OEIS

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A216570

Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 6*b^2.

3, 4, 5, 7, 11, 13, 17, 29, 43, 83, 131, 137, 449, 509, 569, 571, 2971, 4723, 5387, 9677, 14431, 30757, 104911, 130021, 148091, 201107, 397379, 433781, 604711, 931517, 1049897, 1803059

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..32.

Blair Kelly, Factorizations of Fibonacci and Lucas numbers

CROSSREFS

Cf. A000045, A001605.

Sequence in context: A227231 A107036 A001605 * A101762 A342752 A139455

Adjacent sequences: A216567 A216568 A216569 * A216571 A216572 A216573

KEYWORD

nonn

AUTHOR

V. Raman, Sep 08 2012

STATUS

approved