Observation sequence - 2, - 1,2,7,14,23 According to this rule, what is the nth number? | Math enthusiast | Mathematical art

Observation sequence - 2, - 1,2,7,14,23 According to this rule, what is the nth number?

It is not difficult to see that the phase difference is 2N-1
The nth number is n ^ 2-2n-1

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