The sequence N of natural numbers is divided into classes as follows. Show that the sum of the numbers in nth row is `(2n^2+1)`

Explanation

The number of numbers in successive row are `2,4,6` and hence there will be `2n` numbers in `nth` row which will be in the AP of cd `1`. The first term in successive row are


`S=1+3+7+11+....+t_n`


`S=13+7+11+...+t_(n-1)=t_n`


Sutracting `O=1+[2+4+6+(n-1)]`terms`-t_n`


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