The arithmetic mean of 1, 8, 27, 64, … up to n terms is given by
1
\(\frac{{{\rm{n}}\left( {{\rm{n}} + 1} \right)}}{2}\)
2
\(\frac{{{\rm{n}}{{\left( {{\rm{n}} + 1} \right)}^2}}}{2}\)
3
\(\frac{{{\rm{n}}{{\left( {{\rm{n}} + 1} \right)}^2}}}{4}\)
4
\(\frac{{{{\rm{n}}^2}{{\left( {{\rm{n}} + 1} \right)}^2}}}{4}\)