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FibonacciPrimes ​

The Fibonacci primes 2,3,5,13,89,233,…2, 3, 5, 13, 89, 233, …: Fibonacci numbers that are themselves prime.

FibonacciPrimesthe Fibonacci number F(n)F(n) that is prime, an indexed collection of open infinitude -- only finitely many are known at any time.

Domain: Collections

Details
  • A lazy indexed collection; whether there are infinitely many is open, so Count(FibonacciPrimes)=NaNCount(FibonacciPrimes) = NaN. OEIS A005478.
  • At(FibonacciPrimes,k)At(FibonacciPrimes, k) unranks from a table of Fibonacci indices verified prime by exact bigint primality testing, not a search -- past the point a term exceeds what a numeric collection element can represent exactly (253−12^{53}-1), AtAt answers NaNNaN rather than hang: At(FibonacciPrimes,4)=13At(FibonacciPrimes, 4) = 13 (F(7)F(7)), At(FibonacciPrimes,12)At(FibonacciPrimes, 12) is NaNNaN.
  • Membership goes through Element: Element(89,FibonacciPrimes)Element(89, FibonacciPrimes) is true (F(11)F(11), prime), Element(21,FibonacciPrimes)Element(21, FibonacciPrimes) is false (F(8)=21=3×7F(8)=21=3\times7).

Enumeration

Examples

1 more kept as data, checked against the oracles
About
Examples1
CrosswalkOEIS

See also: Count, At, Element, MersennePrimes, PrimeNumbers