$\"\"$

The sequence $\"\"$ .

The first term of sequence $\"\"$ .

The second term of sequence $\"\"$ .

The third term of sequence $\"\"$ .

Observe the terms of the sequence the numerators are squares of the consecutive natural numbers.

Hence the $\"\"$ term for numerator is $\"\"$ .

The denominator is starts with $\"\"$ and the next term of the denominator is increased by $\"\"$ .

Hence $\"\"$ term for denominator is $\"\"$ .

The even terms of the sequence are negative, so the sequence is multiplied with $\"\"$ .

The $\"\"$ term of the sequence is $\"\"$ .

$\"\"$

The $\"\"$ term of the sequence is $\"\"$ .