login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A075738 Squarefree Fibonacci numbers whose indices are also squarefree. 1
1, 1, 2, 5, 13, 55, 89, 233, 377, 610, 1597, 4181, 10946, 17711, 28657, 121393, 514229, 1346269, 3524578, 5702887, 9227465, 24157817, 39088169, 63245986, 165580141, 433494437, 1836311903, 2971215073, 20365011074, 53316291173 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Fib(10)=55 is there because both 10 and 55 are squarefree.

MAPLE

with(combinat, fibonacci): fib_supM_dsk := proc(n); if (numtheory[issqrfree](n)='true') then if (numtheory[issqrfree](fibonacci(n))='true') then RETURN(fibonacci(n)); fi; fi; end: seq(fib_supM_dsk(i), i=1..100);

MATHEMATICA

Select[With[{nn=70}, Thread[{Range[nn], Fibonacci[Range[nn]]}]], AllTrue[#, SquareFreeQ]&][[All, 2]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 17 2018 *)

CROSSREFS

Cf. A000045, A005117, A061305, A075739.

Sequence in context: A105905 A236513 A214853 * A076999 A306827 A028856

Adjacent sequences:  A075735 A075736 A075737 * A075739 A075740 A075741

KEYWORD

easy,nonn

AUTHOR

Jani Melik, Oct 07 2002

EXTENSIONS

Edited by Don Reble, Nov 05 2005

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 30 04:55 EST 2021. Contains 349418 sequences. (Running on oeis4.)