A138184 Largest prime not exceeding Fibonacci(n) = A000045(n).
2, 3, 5, 7, 13, 19, 31, 53, 89, 139, 233, 373, 607, 983, 1597, 2579, 4177, 6763, 10939, 17707, 28657, 46351, 75017, 121379, 196387, 317797, 514229, 832003, 1346249, 2178283, 3524569, 5702867, 9227443, 14930341, 24157811, 39088157, 63245971
Offset: 3
Examples
a(8) = 19 because 19 is the largest prime not exceeding 21 = A000045(8).
Links
- Harry J. Smith, Table of n, a(n) for n = 3..657
Programs
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Maple
A138184 := proc(n) prevprime(combinat[fibonacci](n)+1) ; end: seq(A138184(n),n=3..45) ; # R. J. Mathar, Apr 22 2008
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Mathematica
PrimePrev[n_]:=Module[{k=n},While[ !PrimeQ[k],k-- ];k];f[n_]:=Fibonacci[n];lst={};Do[AppendTo[lst,PrimePrev[f[n]]],{n,5!}];lst (* Vladimir Joseph Stephan Orlovsky, Feb 26 2010 *)
Formula
Extensions
Edited and extended by R. J. Mathar, Apr 22 2008
Offset changed from 4 to 3 by Harry J. Smith, Jan 02 2009