login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (list; graph; refs; listen; history; text; internal format)
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 cross-ref from Charles R Greathouse IV, Sep 08 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified November 19 10:44 EST 2017. Contains 294936 sequences.