cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A138184 Largest prime not exceeding Fibonacci(n) = A000045(n).

Original entry on oeis.org

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

Views

Author

Colm Mulcahy, Mar 04 2008

Keywords

Examples

			a(8) = 19 because 19 is the largest prime not exceeding 21 = A000045(8).

Links

Crossrefs

Cf. A138181, A138182, A138183, A138185.

Programs

  • Maple
    A138184 := proc(n) prevprime(combinat[fibonacci](n)+1) ; end: seq(A138184(n),n=3..45) ; # R. J. Mathar, Apr 22 2008
  • 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

a(n) = A000040(A054782(n)). - R. J. Mathar, Apr 22 2008

Extensions

Edited and extended by R. J. Mathar, Apr 22 2008
Offset changed from 4 to 3 by Harry J. Smith, Jan 02 2009

A138183 Smallest Fibonacci number not less than the n-th prime.

Original entry on oeis.org

2, 3, 5, 8, 13, 13, 21, 21, 34, 34, 34, 55, 55, 55, 55, 55, 89, 89, 89, 89, 89, 89, 89, 89, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 233, 377, 377
Offset: 1

Views

Author

Colm Mulcahy, Mar 04 2008

Keywords

Examples

			a(4) = 8 because the 8 is the smallest Fibonacci number not less than 7 (the 4th prime).

Crossrefs

Cf. A138182, A138185.

Programs

  • Mathematica
    With[{fibs=Fibonacci[Range[20]]},Table[SelectFirst[fibs,#>=n&],{n,Prime[ Range[60]]}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 22 2018 *)
  • PARI
    a(n) = {p = prime(n); i = 0; until ((f = fibonacci(i)) >= p, i++); f;} \\ Michel Marcus, Aug 31 2013

A138181 Largest Fibonacci number not exceeding the n-th prime.

Original entry on oeis.org

2, 3, 5, 5, 8, 13, 13, 13, 21, 21, 21, 34, 34, 34, 34, 34, 55, 55, 55, 55, 55, 55, 55, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 89, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 144, 233, 233
Offset: 1

Views

Author

Colm Mulcahy, Mar 04 2008

Keywords

Comments

a(n) = largest summand in the Zeckendorf representation of the n-th prime

Examples

			a(4)=5 because 5 is the largest Fibonacci number not exceeding 7 (the 4th prime)

Crossrefs

Cf. A138182, A138183, A000040, A000045.

Programs

  • Mathematica
    With[{rf=Reverse[Fibonacci[Range[20]]]},Flatten[Table[Select[rf,#<=Prime[ n]&,1],{n,60}]]] (* Harvey P. Dale, May 25 2013 *)

Extensions

Corrected by Harvey P. Dale, May 25 2013
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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