A075739 Nonsquarefree Fibonacci numbers whose indices are also not squarefree.

144, 2584, 46368, 75025, 14930352, 4807526976, 12586269025, 86267571272, 225851433717, 1548008755920, 498454011879264, 2111485077978050, 160500643816367088, 2880067194370816120, 51680708854858323072, 354224848179261915075, 16641027750620563662096

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Example

Fib(18)=2584 is there because neither 18 nor 2584 is squarefree.

Maple

with(combinat, fibonacci): fib_supM_ndsk := proc(n); if (numtheory[issqrfree](n)='false') then if (numtheory[issqrfree](fibonacci(n))='false') then RETURN(fibonacci(n)); fi; fi; end: seq(fib_supM_ndsk(i), i=1..200);

Mathematica

Select[Table[{n, Fibonacci[n]}, {n, 300}], NoneTrue[#, SquareFreeQ]&][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 20 2019 *)

Crossrefs

Cf. A000045, A013929, A061899, A075738.

Sequence in context: A121344 A232819 A185745 * A074316 A264107 A231584

Adjacent sequences: A075736 A075737 A075738 * A075740 A075741 A075742

Keyword

easy,nonn

Author

Jani Melik, Oct 07 2002

Extensions

Edited by Don Reble, Nov 05 2005

More terms from Harvey P. Dale, Aug 20 2019

Status

approved