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A107038
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First differences of indices of squarefree Fibonacci numbers.
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2
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1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1
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OFFSET
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0,5
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COMMENTS
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LINKS
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MAPLE
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with(numtheory): with(combinat): a:=proc(n) if mobius(fibonacci(n))<>0 then n else fi end:A:=[seq(a(n), n=1..180)]:seq(A[j]-A[j-1], j=2..nops(A)); # Emeric Deutsch, May 30 2005
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MATHEMATICA
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Range[200] // Select[#, SquareFreeQ[Fibonacci[#]]&]& // Differences (* Jean-François Alcover, Aug 29 2024 *)
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PROG
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(GAP) P1:=List(List(List([1..180], n->Fibonacci(n)), Factors), Collected);;
P2:=Positions(List(List([1..Length(P1)], i->List([1..Length(P1[i])], j->P1[i][j][2])), Set), [1]);; a:=List([1..Length(P2)-1], j->P2[j+1]-P2[j]); # Muniru A Asiru, Jul 06 2018
(PARI) lista(nn) = {my(v = select(x->issquarefree(x), vector(nn, k, fibonacci(k)), 1)); vector(#v-1, k, v[k+1] - v[k]); } \\ Michel Marcus, Jul 09 2018
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CROSSREFS
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KEYWORD
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nonn,changed
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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