

A180422


Largest prime immediately preceding a Fibonacci number.


4



2, 3, 7, 11, 19, 31, 53, 83, 139, 229, 373, 607, 983, 1583, 2579, 4177, 6763, 10939, 17707, 28649, 46351, 75017, 121379, 196387, 317797, 514219, 832003, 1346249, 2178283, 3524569, 5702867, 9227443, 14930341, 24157811, 39088157, 63245971
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OFFSET

4,1


COMMENTS

Limit ratio of two consecutive elements of this sequence is phi=1.61803... the golden ratio.


LINKS

Harvey P. Dale, Table of n, a(n) for n = 4..1000


EXAMPLE

a(7)=53 that is the prime number preceding 55=fib(10).
fib(1)=1, fib(2)=1 and fib(3)=2 are not accounted.


MATHEMATICA

NextPrime[#, 1]&/@Fibonacci[Range[4, 40]] (* Harvey P. Dale, Oct 31 2013 *)


PROG

(PARI) a(n)=precprime(fibonacci(n)1)


CROSSREFS

Cf. A138184, A000045
Sequence in context: A210394 A211203 A158709 * A055502 A003173 A159262
Adjacent sequences: A180419 A180420 A180421 * A180423 A180424 A180425


KEYWORD

nonn


AUTHOR

Carmine Suriano, Sep 03 2010


EXTENSIONS

Program and crossref from Charles R Greathouse IV, Sep 08 2010


STATUS

approved



