Question 742937
A(n)=3+2(-1)^n 
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a(1) = 3+2*-1 = 1
a(2) = 3+2*1 = 5
a(3) = 3+2*-1 = 1
a(4) = 3+2*1 = 5
a(5) = 3+2*-1 = 1
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Not an arithmetic sequence.
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Cheers,
Stan H.