Find the sum to n terms of the series whose nth term is
`n^2+2^n`.

Explanation

`sum n^2+2^n`


`sum n^2 + sum 2^n`


`(n(n+1)(2n+1))/6+(1(2(2^n)-1))/(2-1)`


`(n(n+1)(2+1))/6)+(2(2^n)-1)`