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A075742
Fibonacci numbers, which are the product of an odd number of distinct primes for numbers with the same property (mu(n)=mu(fibonacci(n))=-1).
0
2, 5, 13, 89, 233, 1597, 28657, 514229, 24157817, 433494437, 2971215073, 44945570212853, 190392490709135, 99194853094755497, 83621143489848422977, 1500520536206896083277, 3928413764606871165730
OFFSET
1,1
EXAMPLE
11 is a prime and fibonacci(11)=89 is a prime, 13 is a prime and fibonacci(13)=233 is a prime, but fibonacci(16)=987=3*7*47 and 16 is not squarefree and 30=2*3*5 is the product of an odd number of distinct primes but fibonacci(30)=832040=2^3*5*11*31*61 is not squarefree, ...
MAPLE
with(combinat, fibonacci): m2_supM_fib := proc(n); if (numtheory[mobius](n)=-1) then if (numtheory[mobius](fibonacci(n))=-1) then RETURN(fibonacci(n)); fi; fi; end:
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jani Melik, Oct 07 2002
STATUS
approved