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 A061305 Squarefree Fibonacci numbers. 10
 1, 1, 2, 3, 5, 13, 21, 34, 55, 89, 233, 377, 610, 987, 1597, 4181, 6765, 10946, 17711, 28657, 121393, 196418, 317811, 514229, 1346269, 2178309, 3524578, 5702887, 9227465, 24157817, 39088169, 63245986, 102334155, 165580141, 433494437, 701408733, 1134903170, 1836311903 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Union of A074691 and A075735. - R. J. Mathar, Feb 06 2010 About 60% of entries are of the form 4k+1; 20% are of the form 4k+2; 20% are of the form 4k+3. Obviously no term is divisible by 4. - Carmine Suriano, Feb 27 2014 Contains A030426 as a subsequence unless there exist Wall-Sun-Sun primes. - Max Alekseyev, Jan 04 2018 LINKS Amiram Eldar, Table of n, a(n) for n = 1..1080 (terms 1..200 from Zak Seidov) FORMULA Set difference of A000045 and A061899. a(n) = A000045(A037918(n)). - R. J. Mathar, Feb 16 2010 EXAMPLE 55 = 5 * 11 is a squarefree Fibonacci number. MATHEMATICA a={}; Do[f=Fibonacci[n]; If[SquareFreeQ[f], AppendTo[a, f]], {n, 1, 50}]; a (* Vladimir Joseph Stephan Orlovsky, Jul 22 2008 *) Select[Fibonacci[Range[50]], SquareFreeQ] (* Harvey P. Dale, Aug 26 2021 *) PROG (PARI) { n=0; g=0; f=1; for (i=1, 500, if (issquarefree(g), write("b061305.txt", n++, " ", g)); if (n==200, break); s=f; f+=g; g=s ) } \\ Harry J. Smith, Jul 21 2009 CROSSREFS Intersection of A000045 and A005117. Sequence in context: A173830 A224223 A238497 * A177374 A142881 A163159 Adjacent sequences: A061302 A061303 A061304 * A061306 A061307 A061308 KEYWORD nonn,easy AUTHOR Amarnath Murthy, Apr 26 2001 EXTENSIONS More terms from Asher Natan Auel (auela(AT)reed.edu), May 14 2001 Mathematica updated by Jean-François Alcover, Jul 04 2013 STATUS approved

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Last modified February 7 12:36 EST 2023. Contains 360116 sequences. (Running on oeis4.)